106
METRIC MIL-STD-188-125-1 17 July 1998 SUPERSEDING MIL-STD-188-125A 15 February 1994 ’(3$570(172)’()(16( ,17(5)$&(67$1’$5’ HIGH-ALTITUDE ELECTROMAGNETIC PULSE (HEMP) PROTECTION FOR GROUND-BASED C I FACILITIES PERFORMING CRITICAL, 4 TIME-URGENT MISSIONS PART 1 FIXED FACILITIES AMSC N/A AREA TCSS DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

MIL-STD-188-125-1 High-Altitude Electromagnetic Pulse ...futurescience.com/emp/MIL-STD-188-125-1.pdf · HIGH-ALTITUDE ELECTROMAGNETIC PULSE (HEMP) PROTECTION ... Altitude Electromagnetic

Embed Size (px)

Citation preview

METRIC

MIL-STD-188-125-117 July 1998SUPERSEDINGMIL-STD-188-125A15 February 1994

'(3$570(17�2)�'()(16(

,17(5)$&(�67$1'$5'

HIGH-ALTITUDE ELECTROMAGNETIC PULSE (HEMP) PROTECTIONFOR GROUND-BASED C I FACILITIES PERFORMING CRITICAL,4

TIME-URGENT MISSIONS

PART 1FIXED FACILITIES

AMSC N/A AREA TCSS

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

MIL-STD-188-125-1

ii

HIGH-ALTITUDE ELECTROMAGNETIC PULSE (HEMP) PROTECTION FOR FIXED GROUND-BASED C I FACILITIES PERFORMING CRITICAL,4

TIME-URGENT MISSIONS

F O R E W O R D

1. This military standard is approved for use by all Departments and Agencies of theDepartment of Defense (DoD).

2. Originally, Military Standard 188 (MIL-STD-188) covered technical standards for tacticaland long-haul communications, but later evolved through revisions (MIL-STD-188A, MIL-STD-188B) into a document applicable to tactical communications only (MIL-STD-188C).

3. The Defense Information Systems Agency (DISA) published DISA circulars (DISAC)promulgating standards and engineering criteria applicable to the long-haul DefenseCommunication System and to the technical support of the National Military CommandSystem.

4. As a result of a Joint Chiefs of Staff action, standards for all military communications arenow being published in a MIL-STD-188 series of documents. The MIL-STD-188 series issubdivided into a MIL-STD-188-100 series, covering common standards for tactical and long-haul communications; a MIL-STD-188-200 series, covering standards for tacticalcommunications only; and a MIL-STD-188-300 series, covering standards for long-haulcommunications only. Emphasis is being placed on developing common standards for tacticaland long-haul communications published in the MIL-STD-188-100 series.

5. This two-part document contains technical requirements and design objectives for high-altitude electromagnetic pulse (HEMP) protection of ground-based systems and facilities thatare nodes in HEMP-hardened networks for performing critical and time-urgent command,control, communications, computer, and intelligence (C I) missions. This part 1 of the4

document addresses HEMP hardening for fixed facilities; Part 2 addresses transportablesystems. The requirements are stringent, in order to avoid both damage and functional upsetsthat prevent mission accomplishment within operationally prescribed timelines. The standardsapply uniformly to all systems and facilities in the end-to-end chain, since disruption of asingle node may result in network failure.

6. Use of the standard for HEMP protection of other fixed ground-based communications-electronics facilities that require HEMP hardening is encouraged to the extent permitted bycost constraints.

MIL-STD-188-125-1

iii

7. Performance, acceptance test, and verification test requirements are contained in the bodyof the standard. HEMP-unique acceptance and verification test techniques are provided inAppendices A, B, and C.

8. Implementation of MIL-STD-188-125-1 is supported by MIL-HDBK-423, "High-Altitude Electromagnetic Pulse (HEMP) Protection for Fixed and Transportable Ground-BasedFacilities, Volume I: Fixed Facilities." The handbook also includes HEMP program planning,management, logistics, and data requirements for critical, time-urgent, fixed ground-basedfacilities.

9. Beneficial comments (recommendations, additions, deletions) and any pertinent datawhich may be of use in improving this document should be addressed to: Defense SpecialWeapons Agency/ESE, 6801 Telegraph Road, Alexandria, VA 22310-3398, by using theStandardization Document Improvement Proposal (DD Form 1426) appearing at the end ofthis document or by letter.

MIL-STD-188-125-1

C O N T E N T S

PARAGRAPH PAGE

iv

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.3 Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.4 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. APPLICABLE DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Government documents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2.1 Specifications, standards, and handbooks. . . . . . . . . . . . . . . . . . . . . . . . 2 2.2.2 Other Government documents, drawings, and publications. . . . . . . . . . . 3 2.3 Non-Government publications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.4 Order of precedence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 Acronyms used in this standard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Sources for definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.1 Aperture point-of-entry (POE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.2 Conductive POE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.3 Continuous wave (CW) immersion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.4 Corrective maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.5 Electromagnetic barrier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.6 Electromagnetic closure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.7 Electromagnetic stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.8 Facility HEMP shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.9 HEMP acceptance test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.10 HEMP hardness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.11 HEMP hardness assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.12 HEMP hardness configuration baseline. . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.13 HEMP hardness critical item (HCI). . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.14 HEMP hardness critical process (HCP). . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.15 HEMP hardness maintenance (HM). . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3.16 HEMP hardness maintenance and hardness surveillance (HM/HS). . . . . 9 3.1.17 HEMP protection subsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3.18 HEMP hardness surveillance (HS).. . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3.19 HEMP hardness surveillance/reverification testing. . . . . . . . . . . . . . . . 10 3.3.20 Low-risk HEMP hardening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

MIL-STD-188-125-1

C O N T E N T S

PARAGRAPH PAGE

v

3.3.21 Main barrier electrical POE protective device. . . . . . . . . . . . . . . . . . . 10 3.3.22 Mission-critical systems (MCS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3.23 Norton equivalent circuit or Norton source. . . . . . . . . . . . . . . . . . . . . . 10 3.3.24 Penetrating conductor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3.25 Penetration entry area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.26 Performance degradation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.27 Point-of-entry (POE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.28 POE protective device or POE treatment. . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.29 Preventive maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.30 Primary special electrical POE protective device. . . . . . . . . . . . . . . . . . 11 3.3.31 Protected volume. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.32 Pulsed current injection (PCI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.33 Residual internal stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3.34 Retrofit HEMP hardening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.35 Secondary special electrical POE protective device. . . . . . . . . . . . . . . . 12 3.3.36 Shielded enclosure leak detection system (SELDS). . . . . . . . . . . . . . . . 12 3.3.37 Special protective measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.38 Special protective volume. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.39 Verification testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.40 Vulnerability threshold (of an equipment). . . . . . . . . . . . . . . . . . . . . . . 12 3.3.41 Waveguide below cutoff (WBC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.42 Waveguide-below-cutoff array. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4. GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.1.1 HEMP protection overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.1.2 Integration with related requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.2 Hardness program overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.3 HEMP hardening design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.1 Facility shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.2 POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.3 MCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.3.1 MCS within the electromagnetic barrier.. . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.3.2 MCS outside the electromagnetic barrier. . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.3.3 HEMP-hardened electrical power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.3.4 Special protective measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.4 HEMP testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.4.1 Quality assurance program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.4.2 Acceptance testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.4.3 Verification testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

MIL-STD-188-125-1

C O N T E N T S

PARAGRAPH PAGE

vi

4.5 HM/HS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.5.1 HM/HS program development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.5.2 HM/HS program implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5. DETAILED REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.1 HEMP protection subsystem topology. . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.1.1 Electromagnetic barrier topology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.1.2 Penetration entry area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2 Facility grounding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2.1 Equipotential ground plane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2.2 Grounding to the facility HEMP shield. . . . . . . . . . . . . . . . . . . . . . . . . 18 5.3 Facility HEMP shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.1 Shielding effectiveness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.2 Shield configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.3 Shield monitoring capability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.4 Shield construction quality assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.5 Shield acceptance testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.3.5.1 Facility shield modifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.4 Architectural POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.4.1 HEMP protection for architectural POEs. . . . . . . . . . . . . . . . . . . . . . . . 19 5.4.2 Personnel entryways and exits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.4.2.1 Waveguide entryway dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.4.2.2 Entryway shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.4.2.3 Entryway shielded doors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.4.2.4 Entryway interlocks and alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.4.3 Equipment accesses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.4.4 Acceptance testing for architectural POE protective devices. . . . . . . . . . 22 5.5 Mechanical POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.5.1 HEMP protection for mechanical POEs. . . . . . . . . . . . . . . . . . . . . . . . . 23 5.5.2 Piping POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.5.3 Ventilation POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.5.4 Acceptance testing for mechanical POE protective devices. . . . . . . . . . 23 5.6 Structural POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.6.1 HEMP protection for structural POEs. . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.6.2 Acceptance testing for structural POE protective treatments. . . . . . . . . . 25 5.7 Electrical POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.7.1 HEMP protection for electrical POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.7.2 Commercial electric power feeder POEs. . . . . . . . . . . . . . . . . . . . . . . . 26 5.7.2.1 Commercial power main barrier POE protective device requirements . . 26 5.7.3 Other electrical power feeder POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

MIL-STD-188-125-1

C O N T E N T S

PARAGRAPH PAGE

vii

5.7.3.1 Electrical power main barrier POE protective device requirementsfor unrestricted lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.7.3.2 Electrical power main barrier POE protective device requirements for restricted lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.7.4 Audio and data line POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.7.4.1 Standard audio and data lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.7.4.2 Nonstandard audio and data lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.7.4.2.1 Nonstandard audio and data main barrier POE protective

device requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 5.7.5 Electrical control and signal line POEs.. . . . . . . . . . . . . . . . . . . . . . . . . 33 5.7.5.1 Main barrier POE protective device requirements for unrestricted

control and signal lines operating at voltages less than 90 V .. . . . . 33 5.7.5.2 Main barrier POE protective device requirements for unrestricted

control and signal lines operating at voltages greater than 90 V . . . 33 5.7.5.3 Main barrier POE protective device requirements for restricted

control and signal lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.7.6 RF communications antenna line POEs.. . . . . . . . . . . . . . . . . . . . . . . . . 34 5.7.6.1 Antenna line POE protective device requirements.. . . . . . . . . . . . . . . . . 34 5.7.6.1.1 Signal conductor injection for receive-only antennas. . . . . . . . . . . . . . . 34 5.7.6.1.2 Signal conductor injection for transmit antennas. . . . . . . . . . . . . . . . . . 35 5.7.6.1.3 Shield injection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 5.7.7 Conduit shielding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 5.7.7.1 HEMP protection using conduit shielding. . . . . . . . . . . . . . . . . . . . . . . 35 5.7.7.2 Conduit requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.7.8 Acceptance testing of main barrier electrical POE protective devices . . . 37 5.8 Special protective measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5.8.1 MCS outside the main electromagnetic barrier. . . . . . . . . . . . . . . . . . . . 37 5.8.1.1 RF communications antennas outside the main electromagnetic barrier . 37 5.8.2 MCS inside the main electromagnetic barrier. . . . . . . . . . . . . . . . . . . . . 38 5.8.3 Special protective volumes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.8.3.1 Special protective volumes for piping POEs. . . . . . . . . . . . . . . . . . . . . . 38 5.8.3.1.1 Special waveguide requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.8.3.1.2 Special protective barriers for piping POEs. . . . . . . . . . . . . . . . . . . . . . 38 5.8.3.2 Special protective volumes for electrical POEs. . . . . . . . . . . . . . . . . . . 38 5.8.3.2.1 Special protective barriers for electrical POEs. . . . . . . . . . . . . . . . . . . . 40 5.8.3.2.2 Primary special electrical POE protective device requirements. . . . . . . . 40 5.8.3.2.3 Secondary special electrical POE protective device requirements. . . . . . 40 5.8.3.2.4 MCS in a special protective volume. . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.8.4 Acceptance testing for special protective measures. . . . . . . . . . . . . . . . . 40 5.8.4.1 Special protective measures for MCS. . . . . . . . . . . . . . . . . . . . . . . . . . . 40

MIL-STD-188-125-1

C O N T E N T S

PARAGRAPH PAGE

viii

5.8.4.2 Special protective barriers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.9 Reliability and maintainability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.10 Safety and human engineering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.11 Testability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.12 Corrosion control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.13 Configuration management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.14 Verification testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.14.1 CW immersion testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.14.2 PCI verification testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.14.3 Verification for special protective measures. . . . . . . . . . . . . . . . . . . . . . 43 5.14.3.1 Verification of special protective measures for MCS. . . . . . . . . . . . . . . 43 5.14.3.2 Verification of special protective barriers. . . . . . . . . . . . . . . . . . . . . . . . 43 5.15 HM/HS program requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.1 HS/reverification test procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.2 Maintenance and inspection procedures. . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.3 Supply support requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.4 Training requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.5 Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.15.6 Delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.15.7 Implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6. NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.1 Intended use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.2 Issues of DoDISS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.3 Subject term (key word) listing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.4 Changes from previous issue. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

FIGURE

1 Minimum HEMP shielding effectiveness requirements (measured IAWprocedures of Appendix A). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2 Typical waveguide and vestibule entryways. . . . . . . . . . . . . . . . . . . . . . . . 21 3 Typical waveguide-below-cutoff piping POE protective devices. . . . . . . . 24 4 Typical waveguide-below-cutoff array ventilation POE

protective device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5 Typical electrical POE protective device. . . . . . . . . . . . . . . . . . . . . . . . . . 27 6 Typical special protective volumes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

MIL-STD-188-125-1

C O N T E N T S

ix

TABLE

I Injected pulse characteristics and residual internal stress limits for classes of electrical POEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

II Maximum conduit length as a function of conduitoutside diameter (OD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

APPENDIX

A SHIELDING EFFECTIVENESS (SE) TEST PROCEDURES . . . . . . . 48

B PULSED CURRENT INJECTION (PCI) TEST PROCEDURES . . . . . 60

C CONTINUOUS WAVE (CW) IMMERSION TEST PROCEDURES . . 82

CONCLUDING MATERIAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

MIL-STD-188-125-1

This part of the standard addresses fixed facilities only. A fixed ground-based facility, for purposes of this1

standard, consists of equipment in a permanent building or shelter that provides survivable C I capabilities at a fixed4

geographical location. HEMP hardening measures for transportable systems are contained in MIL-STD-188-125-2.

1

1. SCOPE

1.1 Purpose. This standard establishes minimum requirements and design objectivesfor high-altitude electromagnetic pulse (HEMP) hardening of fixed ground-based facilities1

that perform critical, time-urgent command, control, communications, computer, andintelligence (C I) missions. Facilities required to fully comply with the provisions of the4

standard will be designated by the Joint Chiefs of Staff, a Military Department Headquarters,or a Major Command.

1.2 Scope. This standard prescribes minimum performance requirements for low-riskprotection from mission-aborting damage or upset due to HEMP threat environments definedin MIL-STD-2169. This standard also addresses minimum testing requirements fordemonstrating that prescribed performance has been achieved and for verifying that theinstalled protection subsystem provides the operationally required hardness for the completedfacility. If the prescribed testing results in any hardware damage or functional upsets, theoperational authority for the facility will make the determination whether the observed event ismission aborting.

1.3 Applications. This standard defines the design and testing criteria for specificallydesignated fixed ground-based facilities in HEMP-hardened, critical, time-urgent C I4

networks. Such nodes include subscriber terminals and data processing centers, transmittingand receiving communications stations, and relay facilities. The standard applies to both newconstruction and retrofit of existing facilities. Although only local portions of facilityinterconnects are addressed, it is assumed that survivable long-haul communications paths,fiber optic links, or other hardened interconnects between facilities will be provided asrequired for mission accomplishment. Use of the standard for HEMP protection of otherground-based communications-electronics facilities that require HEMP hardening is alsoencouraged.

1.4 Objectives. Survivable C I capabilities are essential to a credible military deterrent. 4

This standard supports nuclear survivability objectives by providing a standardized, low-riskprotection approach for fixed ground-based facilities in HEMP-hardened C I networks. These4

uniform requirements ensure balanced HEMP hardening for all critical facilities in thenetwork.

MIL-STD-188-125-1

2

2. APPLICABLE DOCUMENTS

2.1 General. The documents listed in this section are specified in sections 3, 4, and 5 ofthis standard. This section does not include documents cited in other sections of this standardor recommended for additional information or as examples. While every effort has been madeto ensure the completeness of this list, document users are cautioned that they must meet allspecified requirements documents cited in sections 3, 4, and 5 of this standard, whether or notthey are listed.

2.2 Government documents.

2.2.1 Specifications, standards, and handbooks. The following specifications, standards,and handbooks form a part of this document to the extent specified herein. Unless otherwisespecified, the issues of these documents are those listed in the effective issue of theDepartment of Defense Index of Specifications and Standards (DoDISS) and supplementthereto (see 6.2).

STANDARDS

FEDERAL

FED-STD-1037 – Glossary of Telecommunication Terms

DEPARTMENT OF DEFENSE

MIL-STD-100 – Engineering Drawing PracticesMIL-STD-2169 – High-Altitude Electromagnetic Pulse (HEMP)

Environment (U) (document is classified Secret)

HANDBOOKS

DEPARTMENT OF DEFENSE

MIL-HDBK-419 – Grounding, Bonding, and Shielding for ElectronicEquipment and Facilities

MIL-HDBK-423 – High-Altitude Electromagnetic Pulse (HEMP)Protection for Fixed and Transportable Ground-BasedFacilities, Volume I: Fixed Facilities

(Unless otherwise indicated, copies of the above specifications, standards, and handbooks areavailable from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D,Philadelphia, PA 19111-5094. Requests for MIL-STD-2169 should indicate that the

MIL-STD-188-125-1

3

document is classified, and contractor requests require endorsement by the DoD contractingactivity.)

2.2.2 Other Government documents, drawings, and publications. The following otherGovernment documents, drawings, and publications form a part of this standard to the extentspecified herein. Unless otherwise specified, the issues are those cited in the solicitation.

PUBLICATIONS

JOINT PUB 1-02 – Department of Defense Dictionary of Military andAssociated Terms

FORMS

DD Form 2639 – Hardness Critical Label

DD Form 2640 – Hardness Critical Tag

(Copies of publications and forms required by contractors in connection with specificacquisition functions should be obtained from the contracting activity or as directed by thecontracting officer.)

2.3 Non-Government publications. The following documents form a part of thisdocument to the extent specified herein. Unless otherwise specified, the issues of thedocuments which are Department of Defense (DoD) adopted are those listed in the issue of theDoDISS cited in the solicitation. The issues of documents not listed in the DoDISS are theissues of the documents cited in the solicitation (see 6.2).

ANSI C63.14 – American National Standard Dictionary forTechnologies of Electromagnetic Compatibility(EMC), Electromagnetic Pulse (EMP), andElectrostatic Discharge (ESD)

(Applications for copies should be addressed to the Institute for Electrical and ElectronicsEngineers [IEEE], 445 Hoes Lane, Post office Box 1331, Piscataway NJ 08855-1331.)

NEPA 101 – Life Safety Code

(Applications for copies should be addressed to the National Fire Protection Association[NFPA], Batterymarch Park, Quincy, MA 02269.)

MIL-STD-188-125-1

4

2.4 Order of precedence. In the event of a conflict between the text of this documentand the references cited herein, the text of this document takes precedence. Nothing in thisdocument, however, supersedes applicable laws and regulations unless a specific exemptionhas been obtained.

MIL-STD-188-125-1

5

3. DEFINITIONS

3.1 Acronyms used in this standard. The acronyms used in this standard are defined asfollows:

a. A – Ampere

b. ac – Alternating Current

c. C I – Command, Control, Communications, Computer, and Intelligence4

d. cm – Centimeter

e. CW – Continuous Wave

f. dB – Decibel

g. dBm – Power in dB referred to one milliwatt

h. dc – Direct Current

i. DoD – Department of Defense

j. DoDISS – Department of Defense Index of Specifications and Standards

k. DR – Dynamic Range

l. EMP – Electromagnetic Pulse

m. ESA – Electric Surge Arrester

n. FGBC I – Fixed Ground-Based C I4 4

o. F/O – Fiber Optics

p. ft – Foot

q. FWHM – Full-Width at Half-Maximum Amplitude

r. GHz – Gigahertz

s. GPIB – General Purpose Interface Bus

MIL-STD-188-125-1

6

t. HCI – Hardness Critical Item

u. HCP – Hardness Critical Process

v. HEMP – High-Altitude Electromagnetic Pulse

w. HM – Hardness Maintenance

x. HM/HS – Hardness Maintenance and Hardness Surveillance

y. HS – Hardness Surveillance

z. Hz – Hertz

aa. IAW – In Accordance With

bb. IEEE – Institute of Electrical and Electronics Engineers

cc. in – Inch

dd. kA – Kiloampere

ee. kHz – Kilohertz

ff. m – Meter

gg. mA – Milliampere

hh. MCS – Mission-Critical Systems

ii. MHz – Megahertz

jj. MR – Measurement Range

kk. ms – Millisecond

ll. NFPA – National Fire Protection Association

mm. ns – Nanosecond

nn. OD – Outside Diameter

oo. PCI – Pulsed Current Injection

MIL-STD-188-125-1

7

pp. POE – Point-of-Entry

qq. RF – Radio Frequency

rr. s – Second

ss. SE – Shielding Effectiveness

tt. SE – Shielding Effectiveness (Magnetic Field)M

uu. SE – Shielding Effectiveness (Plane Wave)PW

vv. SE – Shielding Effectiveness (Resonant Range)R

ww. SELDS – Shielded Enclosure Leak Detection System

xx. TEMPEST – A term used to describe a methodology for controlling radiated andconducted emanations of classified information

yy. V – Volt

zz. WBC – Waveguide Below Cutoff

aaa. µs – Microsecond

bbb. 6 – Ohm

3.2 Sources for definitions. Sources for definitions of terms used in this standard, inorder of decreasing priority, are as follows:

a. FED-STD-1037, "Glossary of Telecommunication Terms"

b. JOINT PUB 1-02, "Department of Defense Dictionary of Military and AssociatedTerms"

c. MIL-HDBK-423, "High-Altitude Electromagnetic Pulse (HEMP) Protection forFixed and Transportable Ground-Based Facilities, Volume I: Fixed Facilities"

d. ANSI C63.14, "American National Standard Dictionary for Technologies ofElectromagnetic Compatibility (EMC), Electromagnetic Pulse (EMP), and ElectrostaticDischarge (ESD)"

MIL-STD-188-125-1

8

e. MIL-HDBK-419, "Grounding, Bonding, and Shielding for Electronic Equipment andFacilities"

f. MIL-STD-100, "Engineering Drawing Practices"

3.3 Definitions.

3.3.1 Aperture point-of-entry (POE). An intentional or inadvertent hole, crack, opening,or other discontinuity in the HEMP shield surface. Intentional aperture POEs are provided forpersonnel and equipment entry and egress and for fluid flow (ventilation and piped utilities)through the electromagnetic barrier.

3.3.2 Conductive POE. An electrical wire or cable or other conductive object, such as ametal rod, that passes through the electromagnetic barrier. Conductive POEs are also calledpenetrating conductors.

3.3.3 Continuous wave (CW) immersion. A test method for measuring theelectromagnetic responses induced on an electromagnetic barrier and other items ofinterest (e.g., cables or conduits) illuminated by a CW electric or magnetic field.

3.3.4 Corrective maintenance. All unscheduled maintenance actions. HEMP correctivemaintenance action is undertaken when excessive degradation or failure of a hardness criticalitem is detected, to restore the HEMP protection subsystem to a satisfactory condition andlevel of performance. Corrective maintenance includes removal, repair or replacement,reassembly, and checkout of the completed work.

3.3.5 Electromagnetic barrier. The topologically closed surface created to prevent orlimit HEMP fields and conducted transients from entering the enclosed space. Theelectromagnetic barrier consists of the facility HEMP shield and POE treatments; it enclosesthe protected volume and special protective volumes, if required..

3.3.6 Electromagnetic closure. A treatment to prevent excessive electromagnetic fieldleakage at an aperture POE. Examples of closure techniques at a seam between two metalplates include welding, brazing, or soldering and metal-to-metal contact under pressure appliedwith a mechanical fastening.

3.3.7 Electromagnetic stress. A voltage, current, charge, or electromagnetic field that acts on an equipment. If the electromagnetic stress exceeds the vulnerability threshold of theequipment, mission-aborting damage or upset may occur.

3.3.8 Facility HEMP shield. The continuous conductive housing that substantiallyreduces the coupling of HEMP electric and magnetic fields into the protected volume. Thefacility HEMP shield is part of the electromagnetic barrier.

MIL-STD-188-125-1

9

3.3.9 HEMP acceptance test. An acceptance test of a system, subsystem, or componentperformed to ensure that specified HEMP performance characteristics have been met. HEMPacceptance tests, conducted near the conclusion of a hardening construction or installationcontract, are tests for the purpose of demonstrating that at least minimum performancerequirements of the HEMP protection subsystem have been achieved before the subsystem is accepted by the Government from the contractor.

3.3.10 HEMP hardness. A quantitative description of the resistance of a system orcomponent to temporary or permanent malfunction or degraded performance induced byHEMP. HEMP hardness is achieved through adhering to appropriate design specifications andis verified by one or more test and analysis techniques.

3.3.11 HEMP hardness assurance. Procedures and activities performed during theconstruction or production phase to confirm that the end product meets the HEMP hardnessdesign specifications. Hardness assurance includes those aspects of quality assurance that dealwith hardening component and subassembly testing, acceptance testing, and initial verificationtesting to confirm that design specifications have been met.

3.3.12 HEMP hardness configuration baseline. The functional and physicalcharacteristics of the HEMP protection measures achieved in the "as-built" facility anddocumented in the facility drawings and technical manuals.

3.3.13 HEMP hardness critical item (HCI). An item at any assembly level havingperformance requirements for the purpose of providing HEMP protection. Nuclear HCIsprovide protection from environments produced by a nuclear event or are specially designed tooperate under nuclear weapon (device)-derived stresses. HEMP HCIs are the elements of theHEMP protection subsystem. A hardness critical assembly is a top-level definable unit ofHEMP HCIs and other components, such as mounting hardware and terminal posts, that maynot be hardness critical.

3.3.14 HEMP hardness critical process (HCP). A process, specification, or procedurethat must be followed exactly to ensure that the associated HCI attains its requiredperformance.

3.3.15 HEMP hardness maintenance (HM). Preventive maintenance (e.g., adjustments orcleaning) and corrective maintenance (e.g., repairs or replacements) on the HEMP protectionsubsystem or its HCIs and assemblies. These HM activities are intended to eliminate faults orto preserve specified HEMP protection subsystem performance levels.

3.3.16 HEMP hardness maintenance and hardness surveillance (HM/HS). The combinedpreventive maintenance, inspection, test, and repair activities accomplished on a HEMP-protected operational facility to ensure that HEMP hardness is retained throughout the facility

MIL-STD-188-125-1

10

life cycle. HM/HS, along with hardness assurance and hardness configuration management,constitute a total hardness assurance, maintenance, and surveillance program.

3.3.17 HEMP protection subsystem. The electromagnetic barrier and all specialprotective measures installed for the purpose of hardening the mission-critical systems againstthe HEMP environment.

3.3.18 HEMP hardness surveillance (HS). Inspections and tests of the HEMP protectionsubsystem or its HCIs and assemblies. These HS activities are intended to observe andmonitor the condition and performance of the hardening elements and to detect faults.

3.3.19 HEMP hardness surveillance/reverification testing. Testing conducted atprescribed intervals during the operational phase of the facility life cycle for evaluatingwhether the HEMP protection measures continue to provide the required HEMP hardness. HS/reverification test requirements are established in the technical manual. They typicallyrequire repetition of some or all of the test procedures from the original verification testprogram.

3.3.20 Low-risk HEMP hardening. A hardening technique that features a high-qualityelectromagnetic barrier with minimized and protected POEs. Virtually all mission-criticalcommunications-electronics and support equipment are placed in the protected volumeenclosed by the barrier and operate in a relatively benign electromagnetic environment,isolated from the external HEMP stresses. The low-risk approach results in a well-definedHEMP protection subsystem configuration with inherent testability.

3.3.21 Main barrier electrical POE protective device. A protective device installed on anelectrical conductor that penetrates from the system exterior, through the HEMP shield, andinto the protected volume. Main barrier protective devices must meet the performancerequirements of this standard.

3.3.22 Mission-critical systems (MCS). All communications-electronics and supportequipment required to perform critical trans- and post-HEMP attack missions. In the contextof this standard, MCS refer to equipment that must be hardened to perform missions specifiedto be accomplished during or after exposure to a HEMP environment.

3.3.23 Norton equivalent circuit or Norton source. A circuit, consisting of a currentsource in parallel with an impedance, that has equivalent characteristics to those of therepresented circuit over the operating range of interest.

3.3.24 Penetrating conductor. Any electrical wire or cable or other conductive object,such as a metallic rod, that passes through the electromagnetic barrier. Penetrating conductorsare also called conductive POEs.

MIL-STD-188-125-1

11

3.3.25 Penetration entry area. That area of the electromagnetic barrier where longpenetrating conductors (such as an electrical power feeder) and piping POEs are concentrated.

3.3.26 Performance degradation. Changes in one or more performance characteristics ofa component or assembly, such that it no longer operates within the required functional range.

3.3.27 Point-of-entry (POE). A location on the electromagnetic barrier where the shieldis penetrated and HEMP energy may enter the protected volume unless an adequate POEprotective device is provided. POEs are classified as aperture POEs or penetrating conductorsaccording to the type of penetration. They are also classified as architectural, mechanical,structural, or electrical POEs according to the architectural-engineering discipline in whichthey are usually encountered.

3.3.28 POE protective device or POE treatment. The protective measure used to preventor limit HEMP energy from entering the protected volume at a POE. Common POE protectivedevices include waveguides below cutoff and electromagnetic closure plates for aperture POEsand filters and electric surge arresters on penetrating conductors. The three categories ofelectrical POE protective devices installed on penetrating conductors are main barrier POEprotective devices, primary special POE protective devices, and secondary special POEprotective devices.

3.3.29 Preventive maintenance. Scheduled maintenance actions. These actions areperformed on a regular basis. Preventive maintenance includes scheduled adjustments,cleaning, and replacement of items with limited lifetimes.

3.3.30 Primary special electrical POE protective device. A protective device installed onan electrical conductor that penetrates from the system exterior, through the HEMP shield, intoa special protective volume. A primary special protective device is designed to provide themaximum attenuation possible without interfering with the normal operational electricalsignals that are routed on the penetrating conductor.

3.3.31 Protected volume. The three-dimensional space enclosed by the electromagneticbarrier, but not including those spaces that are also within special protective volumes.

3.3.32 Pulsed current injection (PCI). A test method for measuring performance of aPOE protective device on a penetrating conductor. A HEMP threat-relatable transient isinjected on the penetrating conductor at a point outside the electromagnetic barrier, and theresidual internal transient stress is measured inside the barrier.

3.3.33 Residual internal stress. The electromagnetic voltages, currents, charges, or fields that originate from the HEMP environment and penetrate into the protected volume afterattenuation by elements of the electromagnetic barrier.

MIL-STD-188-125-1

12

3.3.34 Retrofit HEMP hardening. An action taken to modify in-service HEMP protectiveequipment. Retrofit HEMP hardening is the installation or substantial upgrade of the HEMPprotection subsystem for an existing facility or equipment.

3.3.35 Secondary special electrical POE protective device. A protective device installedon an electrical conductor that penetrates from a special protective volume into the mainprotected volume. It is used only when necessary to augment the attenuation provided by theprimary special POE protective device and the connected equipment. The total attenuationthrough the primary special POE protective device, the connected equipment, and thesecondary special POE protective device must meet the performance requirements of thisstandard.

3.3.36 Shielded enclosure leak detection system (SELDS). Any of a class ofcommercially available instruments designed for checking shielding effectiveness in themagnetic field test regime. Most of these instruments operate at one or more discretefrequencies, often of the order of 100 kHz.

3.3.37 Special protective measures. All HEMP hardening measures required in additionto implementation of the electromagnetic barrier. Special protective measures are necessaryfor MCS outside the barrier, for MCS that are within the protected volume and experiencedamage or upset during verification testing, and in cases requiring special protective volumes.

3.3.38 Special protective volume. A HEMP-protected space within the facility, whereelectromagnetic stresses due to HEMP may exceed the residual internal stress limits for theprotected volume. The special protective barrier may be a separate shield with protectedpenetrations; more commonly, shielded cables or conduits and equipment cabinets and closedpiping systems are used to provide the needed electromagnetic isolation from the protectedvolume.

3.3.39 Verification testing. Tests conducted for demonstrating that the installed HEMPprotection subsystem provides the required HEMP hardness. These tests are performed afterthe construction and acceptance testing are complete and after the equipment is installed andfunctioning to determine if the operational system suffers mission-aborting damage or upsetdue to simulated HEMP excitations. Verification is normally a Government-conducted testand is not part of a facility construction contract.

3.3.40 Vulnerability threshold (of an equipment). The minimum stress level that causesthe equipment to suffer definite damage or performance degradation. In the context of thisstandard, the vulnerability threshold is the minimum electromagnetic stress that causesmission-aborting damage or upset.

3.3.41 Waveguide below cutoff (WBC). A metallic waveguide whose primary purpose isto attenuate electromagnetic waves at frequencies below the cutoff frequency (rather than

MIL-STD-188-125-1

13

propagating waves at frequencies above cutoff). The cutoff frequency is determined by thetransverse dimensions and geometry of the waveguide and properties of the dielectric materialin the waveguide.

3.3.42 Waveguide-below-cutoff array. An assembly of parallel waveguides below cutoff,with adjacent cells usually sharing common cell walls. A waveguide-below-cutoff array isused when the area of the shield aperture required to obtain adequate fluid flow within pressuredrop limitations is larger than the permissible area of a single waveguide below cutoff.

MIL-STD-188-125-1

HEMP planning, analysis, design, test procedures, test reporting documentation, and requirements for HM/HS2

program development and execution are described in MIL-HDBK-423, Volume I: Fixed Facilities.

14

4. GENERAL REQUIREMENTS

4.1 General.

4.1.1 HEMP protection overview. The need exists for uniform and effective hardening,hardness verification, and hardness maintenance and hardness surveillance of fixed ground-based command, control, communications, computer, and intelligence (FGBC I) systems that4

require network interoperability during and after exposure to HEMP environments. In criticaltime-urgent applications where some momentary upsets, as well as damage, are mission-aborting, the hardening requirements include stringent shielding, POE protection, and specialprotective measures. Since normal operational experience may not indicate the condition ofthe HEMP protection subsystem, thorough verification testing and HM/HS are necessary over the life of the facility. For additional information, refer to supporting handbook MIL-HDBK-423, Volume I: Fixed Facilities.

4.1.2 Integration with related requirements. Elements of the HEMP protection subsystemcan serve multiple purposes. For example, the electromagnetic barrier can also be used tomeet emanations security requirements. HEMP hardening measures should be integrated with those of other electromagnetic disciplines, such as electromagnetic interference/electromagnetic compatibility, lightning protection, and TEMPEST, and with treatments forother hardening requirements. The performance requirements of this standard are for HEMPprotection only; increases in the required performance may be needed for protection fromother electromagnetic environments, in addition to HEMP.

4.2 Hardness program overview. Hardness programs for fixed ground-based systems2

being HEMP hardened in accordance with (IAW) requirements of this standard shallimplement DoD acquisition policy and procedures. Design, engineering, fabrication,installation, and testing activities shall be organized to accomplish the following objectives:

a. To provide a HEMP-protected system design based upon verifiable performancespecifications.

b. To verify hardness levels through a cost-effective program of testing and analysis.

c. During the acquisition process, to develop a maintenance/surveillance program thatsupports the operational phase of life cycle HEMP hardness.

MIL-STD-188-125-1

Although they are not included within the scope of the document, HEMP-hardened interconnects and survivable3

long-haul communication circuits to other hardened facilities in the network must be made available as required formission accomplishment.

15

d. To establish the HEMP configuration baseline, consisting of documentation of the|functional and physical characteristics of the HEMP protection subsystem, and baseline|performance data.|

4.3 HEMP hardening design. Facility protection against the HEMP threat environmentspecified in MIL-STD-2169 shall be achieved with an electromagnetic barrier and withadditional special protective measures, as required. The electromagnetic barrier shall consistof the facility HEMP shield and protective devices for all POEs. Special protective measuresshall be implemented for hardening MCS that must be placed outside the barrier and for otherspecial cases. Reliability, maintainability, safety and human engineering, testability,configuration management, and corrosion control shall be incorporated into the HEMPprotection subsystem design.

4.3.1 Facility shield. The facility HEMP shield shall be a continuous conductive|enclosure that meets or exceeds shielding effectiveness requirements of this standard (see|5.3.1). The shield is normally constructed of a metal, such as steel or copper. Other materials|may be used if they can provide the required shielding effectiveness and are fully compatible|with the POE protective treatments and grounding reuqirements. |

4.3.2 POEs. The number of shield POEs shall be limited to the minimum required foroperational, life-safety, and habitability purposes. Each POE shall be HEMP protected with a POE protective device that satisfies performance requirements of this standard (see 5.4through 5.7).

4.3.3 MCS. All equipment required to perform critical time-urgent missions during trans-and post-attack time periods shall be designated as MCS. MCS includes such items ascommunications-electronics equipment, data processing subsystems, command and controlequipment, local portions of hardened interconnects, and critical support subsystems such as3

power generation, power distribution, and environmental control.

4.3.3.1 MCS within the electromagnetic barrier. All MCS that will operate satisfactorilyand compatibly inside the facility HEMP shield shall be installed within the electromagneticbarrier. No HEMP-unique performance characteristics are required in design and selection ofMCS that will be housed within the barrier.

4.3.3.2 MCS outside the electromagnetic barrier. MCS, such as a radio antenna orevaporative heat exchanger, that must be placed outside the electromagnetic barrier, shall be

MIL-STD-188-125-1

16

provided with special protective measures as required to ensure HEMP hardness in the HEMPthreat environment (see 5.8).

4.3.3.3 HEMP-hardened electrical power. The facility shall be provided with HEMP-hardened electrical power generation and distribution capability sufficient to perform trans-and post-attack missions, without reliance upon commercial electrical power sources.

4.3.4 Special protective measures. Special protective measures shall be implemented incases where HEMP hardness cannot be achieved with the electromagnetic barrier alone. Additional shielding, transient suppression/ attenuation devices, and equipment-level protection shall be provided as required to achieve HEMP hardness. The three categories ofcases requiring special protective measures are as follows:

a. MCS that must be located outside the electromagnetic barrier and, therefore, are notprotected by the barrier (see 5.8.1).

b. MCS that are enclosed within the electromagnetic barrier and experience mission-aborting damage or upset during verification testing, even though the barrier elements satisfyall performance requirements (see 5.8.2).

c. Special protective volumes and barriers to provide supplementary isolation, whenPOE protective devices cannot satisfy the barrier requirements without interfering with facilityoperation (see 5.8.3).

4.4 HEMP testing. The HEMP testing program shall demonstrate that hardnessperformance requirements have been satisfied and that the required HEMP hardness has beenachieved. This program shall include quality assurance testing during facility construction andequipment installation, acceptance testing for the electromagnetic barrier and special protectivemeasures, and verification testing of the completed and operational facility.

4.4.1 Quality assurance program. A quality assurance program shall be implementedduring system construction and installation to demonstrate that the HEMP protectionsubsystem materials and components comply with performance requirements of this standard. The quality assurance test procedures and results shall be documented and retained for use asbaseline configuration and performance data for the HM/HS program.

4.4.2 Acceptance testing. Acceptance of the HEMP protection subsystem shall be basedupon successful demonstrations of compliance with hardness performance requirements of thisstandard. HEMP acceptance tests of the electromagnetic barrier and special protectivemeasures shall be conducted after all related construction work has been completed. Acceptance test procedures and results shall be documented and retained for use as baselineconfiguration and performance data.

MIL-STD-188-125-1

17

4.4.3 Verification testing. After completion of the HEMP protection subsystem andinstallation, operational checks, and acceptance testing of the facility equipment, HEMPhardness of the facility shall be verified through a program of tests and supporting analysis. The verification program shall provide a definitive statement on the HEMP hardness of criticaltime-urgent mission functions at the facility under test. Verification test procedures and resultsshall be documented and retained for use as baseline configuration and performance data.

4.5 HM/HS.

4.5.1 HM/HS program development. HM/HS considerations shall be included in thefacility planning, design, and construction phases to facilitate life cycle survivability and thedevelopment of an effective HM/HS program. The HM/HS program shall be designed tomaintain the protection subsystem at a level of performance that meets the requirements in thisstandard over the life of the facility.

4.5.2 HM/HS program implementation. During the verification phase, baseline data shallbe obtained for the HM/HS program. The HM/HS program shall be implemented in theoperation and support phase of the facility life cycle. Effectiveness of the HM/HS program formaintaining the HEMP protection subsystem performance at the required level shall beperiodically reviewed, and program revisions shall be made when required.

MIL-STD-188-125-1

18

5. DETAILED REQUIREMENTS

5.1 HEMP protection subsystem topology.

5.1.1 Electromagnetic barrier topology. The electromagnetic barrier, consisting of thefacility HEMP shield and POE protective devices, shall be configured to accomplish thefollowing technical requirements:

a. To enclose all MCS except those equipments such as radio antennas, evaporative heatexchangers, or external security sensors, which will not function properly if placed within theprotected volume.

b. To minimize the number of POEs.

c. To minimize requirements for special protective measures internal to the barrier.

d. To facilitate HEMP acceptance and verification testing.

e. To minimize requirements for scheduled HM.

5.1.2 Penetration entry area. As a design objective, there should be a single penetrationentry area on the electromagnetic barrier for all piping and electrical POEs except thoseconnected to external conductors less than 10 m (32.8 ft) in length. The penetration entry areashall be located as far from normal and emergency personnel and equipment accesses andventilation POEs as is permitted by the facility floor plan.

5.2 Facility grounding.

5.2.1 Equipotential ground plane. Fixed ground-based C I facilities shall be grounded4

using the equipotential ground plane method IAW guidance in MIL-HDBK-419. The facilityHEMP shield shall form a major portion of the equipotential ground plane.

5.2.2 Grounding to the facility HEMP shield. Grounds for equipment and structuresenclosed within the protected volume shall be electrically bonded to the inside surface of theshield. Grounds for equipment and structures outside the electromagnetic barrier shall beelectrically bonded to the outside surface of the shield or to the earth electrode subsystem. Ground straps or cables used to connect the facility shield (equipotential ground plane) to theearth electrode subsystem shall be electrically bonded to the outside surface of the shield, andat least one such ground strap or cable shall be located at the penetration entry area. Allgrounding connections to the facility HEMP shield shall be made in a manner that does notcreate POEs.

MIL-STD-188-125-1

19

5.3 Facility HEMP shield.

5.3.1 Shielding effectiveness. The facility HEMP shield, with all POE protective devicesinstalled, shall provide at least the minimum shielding effectiveness shown on figure 1.

5.3.2 Shield configuration. The facility HEMP shield, exclusive of its POEs, shall be a|continuous conductive enclosure, normally constructed of a metal such as steel or copper. The|enclosure shield shall be electromagnetically closed at all seams and joints between adjacent|panels on the wall, ceiling, and floor surfaces. |

5.3.3 Shield monitoring capability. A built-in test capability to at least qualitativelymonitor for electromagnetic shield leakage shall be provided (see 5.11).

5.3.4 Shield construction quality assurance. In-progress inspection and testing of shield|seams and joints, including those used for installation of POE protective devices, should|proceed continuously in parallel with the shield fabrication and assembly activity. |

5.3.5 Shield acceptance testing. After completion of the shield and after installation ofthe POE protective devices, internal equipments, and finish work provided under theconstruction contract, the shield acceptance test shall be conducted to determine if the facilityshield performs IAW minimum requirements of figure 1. The test shall be conducted withPOEs and their protective devices in a normal operating configuration, using shieldingeffectiveness test procedures of Appendix A. All defects found during the acceptance testingshall be corrected, retested, and shown to provide the required performance.

5.3.5.1 Facility shield modifications. If POEs are added or the facility HEMP shield isbreached and repaired after acceptance, shield acceptance testing in the affected area shall berepeated.

5.4 Architectural POEs.

5.4.1 HEMP protection for architectural POEs. HEMP protection for architectural POEs,|including personnel entryways and exits and equipment accesses through the facility shield,|shall be provided with electromagnetic closure, waveguide-below-cutoff techniques, or|combinations of closure and waveguides below cutoff.|

5.4.2 Personnel entryways and exits. HEMP protection for all normal and emergencypersonnel entryways and exits shall be provided with a two-door shielded waveguide-below-cutoff entryway (figure 2a) or with a two-door shielded vestibule (figure 2b). As designobjectives, the number of personnel entryways and exits should be constrained to the minimumrequirements of NFPA 101, entryway doors should be at 90 degrees to each other, and themain personnel entryway should be a waveguide below cutoff.

MIL-STD-188-125-1

F

IGU

RE

1.

M

inim

um H

EM

P s

hiel

ding

effe

ctiv

enes

s re

quire

men

ts (

mea

sure

d IA

W p

roce

dure

s o

f App

endi

x A

).

20

MIL-STD-188-125-1

21

FIGURE 2. Typical waveguide and vestibule entryways

MIL-STD-188-125-1

22

5.4.2.1 Waveguide entryway dimensions. When a waveguide-below-cutoff entryway isused, height and width of the waveguide shall be the minimum dimensions needed toaccommodate the personnel traffic, and the length of the waveguide along its shortest pathshall be at least five times the diagonal dimension of the cross-section. As a design objective,no electrical wiring, piping, or other conductors should run longitudinally inside thewaveguide entryway. Where electrical wiring cannot be eliminated from the entryway, itshould be run in metal conduit. All conduits and other groundable conductors, such as pipesor handrails, in the waveguide entryway should periodically be electrically bonded to theentryway shield.

5.4.2.2 Entryway shield. The entryway shield shall comply with the same requirementsapplicable to the facility HEMP shield (see 5.3). All entryway POEs, either into the facilityprotected volume or to the outside, shall comply with the same requirements applicable toother POEs through the electromagnetic barrier (see 5.5 through 5.7).

5.4.2.3 Entryway shielded doors. When installed, vestibule shielded doors and shielded|doors in waveguides whose height or width is greater than 2.44 m (8 ft) shall provide at least|the minimum shielding effectiveness shown on figure 1. Entryway doors in waveguides|whose height and width do not exceed 2.44 m shall provide at least the minimum resonant|range and plane wave shielding effectiveness shown on figure 1, but are not required to satisfy|the magnetic shielding effectiveness criteria because of the low-frequency attenuation provided|by the waveguide. Exterior shielded doors shall be protected from corrosion and exposure to|blown dust and other natural elements.|

5.4.2.4 Entryway interlocks and alarms. The entryway shielded doors shall be providedwith interlocks to ensure that at least one of the shielded doors remains closed except duringemergency evacuations. The entryway shielded doors shall be provided with an alarm toindicate that the interlock has been overridden or that both shielded doors are open.

5.4.3 Equipment accesses. A protected equipment access POE shall be provided only|when movement of the equipment through a personnel entryway is not practical. HEMP|protection for equipment accesses through the facility HEMP shield shall be provided with|electromagnetic closure. When closed, the equipment access covers shall provide at least the|minimum shielding effectiveness shown on figure 1. Exterior access covers shall be protected|from corrosion and exposure to blown dust and other natural elements.|

5.4.4 Acceptance testing for architectural POE protective devices. Acceptance testing forarchitectural POE protective devices shall be conducted using shielding effectiveness testprocedures of Appendix A. All defects found during the acceptance testing shall be corrected,retested, and shown to provide the required performance.

MIL-STD-188-125-1

23

5.5 Mechanical POEs.

5.5.1 HEMP protection for mechanical POEs. HEMP protection for mechanical POEs,|including piping and ventilation penetrations through the facility HEMP shield, shall be|provided with waveguide-below-cutoff techniques. As design objectives, the number of piping|POEs should be constrained to fewer than 20 and the number of ventilation POEs should be|constrained to fewer than 10.|

5.5.2 Piping POEs. Piping shall penetrate the facility HEMP shield as metallic pipe|sections that are configured as single waveguides below cutoff or WBC arrays (figure 3). |Dielectric hoses or pipes shall be converted to metal piping before penetrating the shield. The|presence of protected piping POEs shall not degrade shielding effectiveness of the facility|HEMP shield below the minimum requirements shown on figure 1.|

|The inside diameter of a single waveguide below cutoff and each of the transverse cell|

dimensions in a WBC array shall be limited such that the waveguide cutoff frequency is at|least 1.5 GHz. The length of the waveguide section shall be sufficient to provide at least 80|dB attenuation at 1 GHz, except where a special protective volume will be established (see|5.8.3.1). No dielectric (glass, plastic, etc.) pipe lining shall be permitted in the waveguide|section. External and internal piping shall be connected at the ends of the waveguide section;|no HEMP-unique requirements apply to these couplings.|

5.5.3 Ventilation POEs. Ventilation ducts shall penetrate the facility HEMP shield in|sections of metallic ducting that are configured as waveguide-below-cutoff array panels|(figure 4). The presence of the protected ventilation POEs shall not degrade shielding|effectiveness of the facility HEMP shield below the minimum requirements shown on figure 1.|

|Each of the transverse cell dimensions of the WBC array shall be limited such that the|

waveguide cutoff frequency is at least 1.5 GHz. The length of the waveguide shall be|sufficient to provide at least 80 dB attenuation at 1 GHz. No conductors shall be permitted to|pass through the waveguide.|

5.5.4 Acceptance testing for mechanical POE protective devices. Acceptance testing formechanical POE protective devices, including those for piping and ventilation penetrations,shall be conducted using shielding effectiveness test procedures of Appendix A. All defectsfound during the acceptance testing shall be corrected, retested, and shown to provide therequired performance.

5.6 Structural POEs.

5.6.1 HEMP protection for structural POEs. HEMP protection for structural POEs,|including beams, columns, and other metallic structural elements that must penetrate the|

MIL-STD-188-125-1

24

FIGURE 3. Typical waveguide-below-cutoff piping POE protective devices.

MIL-STD-188-125-1

25

FIGURE 4. Typical waveguide-below-cutoff array ventilation POE protective device.

electromagnetic barrier, shall be provided with continuous electromagnetic closure between the|penetrating elements and the facility shield. As a design objective, the facility should be|configured to minimize the number of metallic structural elements required to penetrate the|barrier. Nonmetallic structural elements shall not penetrate the electromagnetic barrier.|

5.6.2 Acceptance testing for structural POE protective treatments. Acceptance testing forstructural POE protective treatments shall be conducted using shielding effectiveness testprocedures of Appendix A. All defects found during the acceptance testing shall be corrected,retested, and shown to provide the required performance.

5.7 Electrical POEs.

5.7.1 HEMP protection for electrical POEs. HEMP protection for electrical POEs,|including all power, communications, and control penetrating conductors whether shielded or|unshielded, shall be provided with main barrier transient suppression/attenuation devices|(except under conditions identified in 5.7.7). The presence of protected electrical POEs shall|not degrade shielding effectiveness of the facility HEMP shield below minimum requirements|shown on figure 1.|

MIL-STD-188-125-1

Common mode PCI requirements, waveform details of the injected pulses, circuit test configuration information,4

and additional constraints on the residual internal transient stress are contained in table I and in the PCI test proceduresof Appendix B.

The POE protective device for an intersite commercial power or audio/data line may consist of a transformer or5

dielectric isolator installed on the line side of an electric surge arrester (ESA)/filter assembly, where the transformer ordielectric isolator provides hardening against the long pulse and the ESA/filter provides intermediate and short pulseprotection. The long pulse is injected on the line side of the transformer or dielectric isolator in such a case, and theintermediate and short pulses are injected at the external terminal of the ESA/filter assembly.

26

The main barrier transient suppression/attenuation device (figure 5) shall consist of linear|and nonlinear elements, as required to satisfy the performance requirements. The main barrier|protective device shall limit the norms of the residual internal transient stresses to the|maximums prescribed for each class of electrical POE, when prescribed pulses are injected at|its external terminal (see table I). Additionally, the main barrier protective device shall be|rated to withstand a sufficient number of test pulses at the prescribed peak injection current|without damage or unacceptable performance degradation to accommodate life cycle testing.|

5.7.2 Commercial electrical power feeder POEs. A main barrier transient suppression/attenuation device shall be provided on each penetrating conductor of a commercial electricalpower feeder POE. The section of the commercial power feeder immediately outside theelectromagnetic barrier shall be buried for a length of at least 16 m (52.5 ft). As a designobjective, a maximum of two commercial electrical power feeders should penetrate the facilityHEMP shield.

5.7.2.1 Commercial power main barrier POE protective device requirements. A Norton|source, with a 2500-A short-circuit current, � 20-ns risetime and 500-550-ns full-width at half-|maximum amplitude (FWHM), and source impedance � 60 6, connected to a penetrating|conductor at the main barrier POE protective device external terminal, shall produce a residual|internal transient stress no greater than 10 A and shall not cause device damage or performance|degradation. A Norton source, with a short-circuit current of 250 A, � 1.5-µs risetime and 4|3-5-ms FWHM, and source impedance � 10 6, connected at the main barrier POE protective|device external terminal, shall not cause device damage or performance degradation. A4|Norton source, with a 1000-A short-circuit current, � 0.2-s risetime and 20-25-s FWHM, and|source impedance � 5 6, connected at the main barrier POE protective device external|terminal , shall not cause device damage or performance degradation. If a main barrier POE 5 4|protective device cannot be designed to satisfy the residual internal stress limits without|interfering with operational signals that it is required to pass, a special protective volume shall|be established (see 5.8.3.2). As a design objective, each commercial power feeder should be|provided with a device to automatically disconnect the incoming lines if a HEMP event occurs|or to manually disconnect during alert conditions.|

27

MIL-STD-188-125-1

FIG

UR

E 5

. T

ypic

al e

lect

ric

PO

E p

rote

ctiv

e d

evi

ce.

MIL-STD-188-125-1

28

a. Electrical POEs, except RF antenna line POEs.

Class of Electrical POE

Pulsed Current Injection Requirements1

Type ofInjection

Peak Short-Ckt Current (A)

Risetime(s)

FWHM2

(s)

Commercial Power Lines (Intersite) Short Pulse Short Pulse Intermediate Pulse Intermediate Pulse Long Pulse Long Pulse

Common modeWire-to-groundCommon modeWire-to-groundCommon modeWire-to-ground

5,0002,500

250250

1,0003

1,0003

�2×10-8

�2×10-8

�1.5×10-6

�1.5×10-6

�0.2�0.2

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

3×10 –5x10-3 -3

3×10 –5x10-3 -3

20–253

20–253

Other Power Lines (Intrasite) Unrestricted Lines Short Pulse Short Pulse Restricted Lines Short Pulse Short Pulse

Common modeWire-to-ground

Common modeWire-to-ground

5,0002,500

800800/ or 5004

�2×10-8

�2×10-8

�2×10-8

�2×10-8

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

Audio/Data Lines (Intersite) Short Pulse Short Pulse Intermediate Pulse Intermediate Pulse Long Pulse Long Pulse

Common modeWire-to-groundCommon modeWire-to-groundCommon modeWire-to-ground

5,0005,000/ or 5004

250250

1,000 3

1,000 3

�2×10-8

�2×10-8

�1.5×10-6

�1.5×10-6

�0.2�0.2

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

3×10 –5x10-3 -3

3×10 –5x10-3 -3

20–253

20–253

Control/Signal Lines (Intrasite) Unrestricted Low-Voltage Lines5

Short Pulse Short Pulse Unrestricted High-Voltage Lines5

Short Pulse Short Pulse Restricted Lines Short Pulse Short Pulse

Common modeWire-to-ground

Common modeWire-to-ground

Common-modeWire-to-ground

5,0005,000/ or 5004

5,0005,000/ or 5004

800800/ or 5004

�2×10-8

�2×10-8

�2×10-8

�2×10-8

�2×10-8

�2×10-8

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

Conduit Shields Signal and Low Current Power6

Buried7

Nonburied Medium Current Power6

Buried7

Nonburied High Current Power6

Buried7

Nonburied

Conduit-to-gndConduit-to-gnd

Conduit-to-gndConduit-to-gnd

Conduit-to-gndConduit-to-gnd

8005,000

8005,000

8005,000

�2×10-8

�2×10-8

�2×10-8

�2×10-8

�2×10-8

�2×10-8

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

TABLE I. Injected pulse characteristics and residual internal stress limits for classes of electrical POEs.

MIL-STD-188-125-1

29

TABLE I. Injected pulse characteristics and residual internal stress limits for classes of electrical POEs - Continued.

a. Electrical POEs, except RF antenna line POEs (continued).

Class of Electrical POE

Residual Internal Stress Limits

Type ofMeasurement

Peak ResponseCurrent (A)

Peak Rate ofRise (A/s)

Root Action (A - )

Commercial Power Lines (Intersite) Short Pulse Short Pulse

Bulk currentWire current

�10�10

�1×107

�1×107�1.6×10-1

�1.6×10-1

Intermediate Pulse Intermediate Pulse Long Pulse Long Pulse

Bulk currentWire currentBulk currentWire current

No damage or performance degradationNo damage or performance degradationNo damage or performance degradationNo damage or performance degradation

Other Power Lines (Intrasite) Short Pulse Short Pulse

Bulk currentWire current

�10�10

�1×107

�1×107�1.6×10-1

�1.6×10-1

Audio/Data Lines (Intersite) Short Pulse Short Pulse

Bulk currentWire current

�0.1�0.1

�1×107

�1×107�1.6×10-3

�1.6×10-3

Intermediate Pulse Intermediate Pulse Long Pulse Long Pulse

Bulk currentWire currentBulk currentWire current

No damage or performance degradationNo damage or performance degradationNo damage or performance degradationNo damage or performance degradation

Control/Signal Lines (Intrasite) Low-Voltage Lines5

Short Pulse Short Pulse High-Voltage Lines5

Short Pulse Short Pulse

Bulk currentWire current

Bulk currentWire current

�0.1�0.1

�1.0�1.0

�1×107

�1×107

�1×107

�1×107

�1.6×10-3

�1.6×10-3

�1.6×10-2

�1.6×10-2

Conduit Shields Signal and Low Current Power6

Buried7

Nonburied Medium Current Power6

Buried7

Nonburied High Current Power6

Buried7

Nonburied

Bulk currentBulk current

Bulk currentBulk current

Bulk currentBulk current

�0.1�0.1

�1.0�1.0

�10�10

�1×107

�1×107

�1×107

�1×107

�1×107

�1×107

�1.6×10-3

�1.6×10-3

�1.6×10-2

�1.6×10-2

�1.6×10-1

�1.6×10-1

MIL-STD-188-125-1

30

TABLE I. Injected pulse characteristics and residual internal stress limits for classes of electrical POEs - Continued.

b. RF antenna line POEs.

Class of ElectricalPOE

Pulsed Current Injection Requirements8

Type ofInjection

DominantResponse

Frequency9

(MHz)

Peak Short-Circuit Current

(A)Risetime

(s)FWHM2

(s)

RF antenna lineshield Buried7

NonburiedShield-to-gndShield-to-gnd

Not applicableNot applicable

8005,000

�2×10-8

�2×10-85×10 –5.5×10-7 -7

5×10 –5.5×10-7 -7

RF antenna linesignal conductor

Wire-to-shieldWire-to-shield

�30>30

Threat-level9

Threat-level9�2×10-8

�5×10-95×10 –5.5×10-7 -7

Variable9

Class of ElectricalPOE

Residual Internal Stress Limits

Type ofMeasurement

Peak ResponseCurrent (A)

Peak Rate of Rise(A/s)

Root Action (A - )

Receive onlyantenna line Shield Current �0.1 �1×107

�1.6×10-3

Wire Current �0.1 No damage or performance degradation

Transmit andreceive antennaline

Shield Current �0.1 �1×107�1.6×10-3

Wire Current �1.0 No damage or performance degradation

c. Notes for Table I.

Pulse current injection requirements are in terms of Norton equivalent sources. Short-circuit currents are double1

exponential waveshapes. Source impedances are � 60 6 for the short pulse, � 10 6 for the intermediate pulse, and� 5 6 for the long pulse.

FWHM is pulse full-width at half-maximum amplitude.2

The long pulse peak short-circuit current (1,000 A) and FWHM (20-25 s) are design objectives. Any double3

exponential waveform with peak short-circuit current � 200 A, risetime � 0.2 s, and peak current x FWHM product � 2 x 10 A-s satisfies the minimum requirement.4

MIL-STD-188-125-1

31

TABLE I. Injected pulse characteristics and residual internal stress limits for classes of electrical POEs - Continued.

c. Notes for Table I (continued).

Whichever is larger. N is the number of penetrating conductors in the cable.4

Low-voltage control/signal lines are those with maximum operating voltage < 90 V. High-voltage control/signal lines5

are those with maximum operating voltage � 90 V.

High-current power lines have maximum operating current > 10 A. Medium-current power lines have maximum6

operating current between 1 A and 10 A. Low-current power lines have maximum operating current < 1 A.

An antenna shield is considered buried when it terminates at a buried antenna and less than 1 m (3.3 ft) of its total7

length is not covered by earth or concrete fill. A conduit is considered buried when it connects two protected volumesand less than 1 m (3.3 ft) of its total length is not covered by earth or concrete fill.

Pulse current injection requirements are in terms of Norton equivalent sources. The short pulse generator, with a8

source impedance � 60 6, is used for shield-to-ground injections and for wire-to-shield injections at dominantresponse frequencies � 30 MHz. A charge line pulser, with a source impedance � 50 6, is used for wire-to-shieldinjections at dominant response frequencies > 30 MHz.

The dominant response frequency (or frequencies) and threat-level peak short-circuit current are determined from9

extrapolated coupling measurements. The length 5 of the charge line of the charge line pulser is the quarter-wavelength of the dominant response frequency; 5 = 0.25 c/f, where c = 3 x 10 m/s and f is frequency in Hz.8

______________

5.7.3 Other electrical power feeder POEs. A main barrier transient suppression/attenuation device shall be provided on each penetrating conductor of electrical power feederPOEs that supply internal power to equipment outside the electromagnetic barrier. As a designobjective, internal power should be supplied only to MCS outside the electromagnetic barrier. Nonessential equipment outside the barrier should be powered from an external source.

5.7.3.1 Electrical power main barrier POE protective device requirements for|unrestricted lines. A Norton source, with a 2500-A short-circuit current, � 20-ns risetime and|500-550-ns FWHM, and source impedance � 60 6, connected to a penetrating conductor at|the main barrier POE protective device external terminal, shall produce a residual internal|transient stress no greater than 10 A and shall not cause device damage or performance|degradation. Intermediate and long pulse performance requirements for an intrasite power4|line POE protective device shall be determined by coupling analyses when the length of the|exposed line exceeds 200 m. If a main barrier POE protective device cannot be designed to|satisfy the residual internal stress limits without interfering with operational signals that it is|required to pass, a special protective volume shall be established (see 5.8.3.2).|

MIL-STD-188-125-1

32

5.7.3.2 Electrical power main barrier POE protective device requirements for restricted|lines. Reduced performance requirements apply to POE protective devices for restricted|intrasite power lines that satisfy the following criteria:|

|a. The exposed external section of the power line is less than 5 m (16.4 ft) in length|

|b. The external equipment connected to the power line is physically small, less than 2 m|

(5.1 ft) in its largest dimension||

c. The external equipment is not connected to other electrical conductors (except ground|conductors) or metal pipes; it is either ungrounded or grounded directly to the facility HEMP|shield.|

|The Norton source parameters for restricted intrasite power lines are 800/ or 500-A short-|circuit current (where N is the number of conductors in the cable and the larger amplitude is|chosen), � 20-ns risetime, 500-550-ns FWHM, and � 60-6 source impedance . The residual4|internal transient limits and functional requirements for restricted lines are the same as those|for unrestricted lines. If a main barrier POE protective device cannot be designed to satisfy the|residual internal stress limits without interfering with operational signals that it is required to|pass, a special protective volume shall be established (see 5.8.3.2).|

5.7.4 Audio and data line POEs.

5.7.4.1 Standard audio and data lines. All standard voice and data lines, whethershielded or unshielded, shall be converted to fiber optics outside the electromagnetic barrierand shall penetrate the facility HEMP shield on all-dielectric fiber optic cables. Optoelectronicequipment outside the electromagnetic barrier shall be protected using special protectivemeasures (see 5.8.1), if the associated audio or data line is mission critical. The fiber opticcable POE shall be protected with a waveguide-below-cutoff protective device.

The inside diameter of a fiber optic WBC shall be limited such that the waveguide cutoff|frequency is at least 1.5 GHz. The length of the waveguide shall be sufficient to provide at|least 80 dB attenuation at 1 GHz. No conductors or conducting fluids shall be permitted to|pass through the waveguide; the waveguide-below-cutoff protective device shall be filled or its|ends shall be capped to prevent inadvertent insertion of conductors.|

5.7.4.2 Nonstandard audio and data lines. A main barrier transient suppression/attenuation device shall be provided on each penetrating conductor of shielded or unshieldednonstandard audio or data lines that cannot be practically converted to fiber optics. As adesign objective, a maximum of 20 such nonstandard audio or data lines should be allowed topenetrate the facility HEMP shield.

MIL-STD-188-125-1

33

5.7.4.2.1 Nonstandard audio and data main barrier POE protective device requirements. |A Norton source, with a 5000/ or 500-A short-circuit current (where N is the number of|penetrating conductors in the audio or data cable and the larger amplitude is chosen), � 20-ns|risetime and 500-550-ns FWHM, and source impedance � 60 6, connected to a penetrating|conductor at the main barrier POE protective device external terminal, shall produce a residual|internal transient stress no greater than 0.1 A and shall not cause device damage or|performance degradation. A Norton source, with a 250-A short-circuit current, � 1.5-µs4|risetime and 3-5-ms FWHM, and source impedance � 10 6, connected at the main barrier|POE protective device external terminal, shall not cause device damage or performance|degradation. A Norton source, with a 1000-A short-circuit current, � 0.2-s risetime and 4|20-25-s FWHM, and source impedance � 5 6, connected at the main barrier POE protective|device external terminal , shall not cause device damage or performance degradation. If a5 4 |main barrier POE protective device cannot be designed to satisfy the residual internal transient|stress limits without interfering with operational signals it is required to pass, a special|protective volume shall be established (see 5.8.3.2).|

5.7.5 Electrical control and signal line POEs. A main barrier transient suppression/attenuation device shall be provided on each penetrating conductor of electrical control andsignal lines, whether shielded or unshielded. As a design objective, the number of control andsignal lines penetrating the facility HEMP shield should be minimized. Nonmetallic fiberoptic lines do not require a transient suppression/attenuation device at the barrier.

5.7.5.1 Main barrier POE protective device requirements for unrestricted control and|signal lines operating at voltages less than 90 V. A Norton source, with a 5000/ or 500-A|short-circuit current (where N is the number of penetrating conductors in the control or signal|cable and the larger amplitude is chosen), � 20-ns risetime and 500-550-ns FWHM, and source|impedance � 60 6, connected to a penetrating conductor at the main barrier POE protective|device external terminal, shall produce a residual internal transient stress no greater than 0.1 A|and shall not cause device damage or performance degradation. Intermediate and long pulse4|performance requirements for an intrasite control and signal line POE protective device shall|be determined by coupling analyses when the length of the exposed line exceeds 200 m. If a |main barrier POE protective device cannot be designed to satisfy the residual internal transient|stress limits without interfering with operational signals it is required to pass, a special|protective volume shall be established (see 5.8.3.2).|

5.7.5.2 Main barrier POE protective device requirements for unrestricted control and|signal lines operating at voltages greater than 90 V. A Norton source, with a 5000/ or|500-A short-circuit current (where N is the number of penetrating conductors in the control or|signal cable and the larger amplitude is chosen), � 20-ns risetime and 500-550-ns FWHM, and|source impedance � 60 6, connected to a penetrating conductor at the main barrier POE|protective device external terminal, shall produce a residual internal transient stress no greater|than 1 A and shall not cause device damage or performance degradation. Intermediate and4|long pulse performance requirements for an intrasite control and signal line POE protective|

MIL-STD-188-125-1

34

device shall be determined by coupling analyses when the length of the exposed line exceeds|200 m. If a main barrier POE protective device cannot be designed to satisfy the residual|internal transient stress limits without interfering with operational signals it is required to pass,|a special protective volume shall be established (see 5.8.3.2).|

5.7.5.3 Main barrier POE protective device requirements for restricted control and signal|lines. Reduced performance requirements apply to POE protective devices for restricted|intrasite control and signal lines that satisfy the following criteria:|

|a. The exposed external section of the control or signal line is less than 5 m (16.4 ft) in|

length||

b. The external equipment connected to the control or signal line is physically small,|less than 2 m (5.1 ft) in its largest dimension|

|c. The external equipment is not connected to other electrical conductors (except ground|

conductors) or metal pipes; it is either ungrounded or grounded directly to the facility HEMP|shield.|

|The Norton source parameters for restricted intrasite control and signal lines are 800/ or |500-A short-circuit current (where N is the number of conductors in the cable and the larger|amplitude is chosen), � 20-ns risetime, 500-550-ns FWHM, and � 60-6 source impedance. 4|The residual internal transient limits and functional requirements for restricted lines are the|same as those for unrestricted lines. If a main barrier POE protective device cannot be|designed to satisfy the residual internal stress limits without interfering with operational|signals that it is required to pass, a special protective volume shall be established (see 5.8.3.2).|

5.7.6 RF communications antenna line POEs. A main barrier transient suppression/|attenuation device shall be provided on the signal-carrying conductor of each penetrating RF|communications antenna line. The antenna cable shield shall be circumferentially bonded to|the facility HEMP shield at the POE.|

5.7.6.1 Antenna line POE protective device requirements.

5.7.6.1.1 Signal conductor injection for receive-only antennas. Pulses of the prescribed|waveforms and amplitudes, occurring on the signal-carrying conductor at the antenna terminals|of a receive-only antenna subsystem, shall produce residual internal transient stresses no|greater than 0.1 A on the signal-carrying conductor and shield and shall not cause device|damage or performance degradation. An antenna protective device may be used in4|conjunction with the main barrier POE protective device to achieve the required transient|suppression/attenuation. The waveforms and amplitudes of the pulses to be applied shall be|determined by threat extrapolation of coupling measurements. Coupling measurements shall|be acquired using CW immersion or another threat-relatable method. Coupling and PCI test|

MIL-STD-188-125-1

It may be difficult to design main barrier POE and antenna protective devices that can achieve the residual6

requirement of 1 A for an RF transmit-only or transceiver signal-carrying conductor. Therefore, RF transmitters ortransceivers may require placement in special protective volumes (see 5.8.3.2).

35

details are provided in Appendix B. If the antenna subsystem protection cannot be designed to|satisfy the residual internal transient stress limits without interfering with operational signals it|is required to pass, a special protective volume shall be established (see 5.8.3.2). |

5.7.6.1.2 Signal conductor injection for transmit antennas. Pulses of the prescribed|waveforms and amplitudes, occurring on the signal-carrying conductor at the antenna terminals|of a transmit-only or transceive antenna subsystem, shall produce residual internal transient|stresses no greater than 1 A on the signal-carrying conductor and 0.1 A on the shield and shall6|not cause device damage or performance degradation . An antenna protective device may be4|used in conjunction with the main barrier POE protective device to achieve the required|transient suppression/attenuation. The waveforms and amplitudes of the pulses to be applied|shall be determined by threat extrapolation of coupling measurements. Coupling|measurements shall be acquired using CW immersion or another threat-relatable method. |Coupling and PCI test details are provided in Appendix B. If the antenna subsystem protection|cannot be designed to satisfy the residual internal transient stress limits without interfering|with operational signals it is required to pass, a special protective volume shall be established|(see 5.8.3.2). |

5.7.6.1.3 Shield injection. A Norton source, with an 800-A short-circuit current, � 20-ns|risetime and 500-550-ns FWHM, and source impedance � 60 6, connected to the shield of a|buried antenna cable at a point outside the electromagnetic barrier, shall produce residual|internal transient stresses no greater than 0.1 A on the signal-carrying conductor and shield and|shall not cause POE protective device damage or performance degradation. For a nonburied4|antenna cable, a Norton source, with a 5000-A short-circuit current, � 20-ns risetime and|500–550-ns FWHM, and source impedance � 60 6, connected to the shield at a point outside|the barrier, shall produce residual internal transient stresses no greater than 0.1 A on the signal-|carrying conductor and shield and shall not cause POE protective device damage or|performance degradation. An antenna cable is considered buried when less than 1 m (3.3 ft)4|of its total length is not covered by earth or concrete fill and it terminates at a buried antenna. |The cable is considered nonburied if at least 1 m (3.3 ft) of its total length is not covered or it|terminates at an aboveground antenna.|

5.7.7 Conduit shielding.

5.7.7.1 HEMP protection using conduit shielding. HEMP protection for cable runs|between two protected volumes may be provided using continuous conduit shielding when the|lengths of the runs do not exceed the applicable maximums in table II. Main barrier transient |

|

MIL-STD-188-125-1

36

TABLE II. Maximum conduit length as a function of conduit outside diameter (OD).

Type of Cable Run and Conduit

Maximum Conduit Length (m)

5 cm � OD < 10cm

10 cm � OD < 15cm

15 cm �OD

Signal and Low Current PowerLines Buried Conduit Nonburied Conduit

376

7512

11218

Medium Current Power Lines Buried Conduit Nonburied Conduit

20060

600120

1120180

High Current Power Lines Buried Conduit Nonburied Conduit

200200

600600

1,2001,200

suppression/attenuation devices are not required on the penetrating conductors under these|conditions.|

|Any cable run containing one (or more) control or signal conductors is considered to be a|

signal line. A power cable run containing one or more conductors with maximum operating|currents less than 1.0 A is a low current power line. A power cable run in which the maximum|operating current on the lowest rated conductor is between 1.0 A and 10 A is a medium current|power line. A power cable run containing only power lines with operating currents greater|than 10 A is a high current power line. A conduit is considered buried when less than 1 m |(3.3 ft) of its total length is not covered by earth or concrete fill; it is nonburied if 1 m (3.3 ft)|or more of the total conduit length is not covered.|

5.7.7.2 Conduit requirements. HEMP protection conduits shall be rigid metal conduit,|with circumferentially welded, brazed, or threaded closures at all joints and couplings, pull|boxes, and penetrations through the facility HEMP shields at both ends. A Norton source,|with an 800-A short-circuit current on a buried signal or low current power line conduit and a|5000-A short-circuit current on a nonburied signal or low current power line conduit, � 20 ns|risetime and 500-550-ns FWHM, and source impedance � 60 6, shall produce a residual|internal transient stress no greater than 0.1 A on the wire bundle inside the conduit. The same4|sources connected on the outer surface of a medium or high current power line conduit shall|produce a residual internal transient stress no greater than 10 A, when the operating current on|the lowest rated conductor in the wire bundle inside the conduit is greater than 10 A, and no|greater than 1.0 A when the operating current is between 1.0 A and 10 A.4|

MIL-STD-188-125-1

See MIL-HDBK-423 for methods to determine the upper-bound HEMP stresses and vulnerability thresholds.7

37

5.7.8 Acceptance testing of main barrier electrical POE protective devices. Acceptancetesting of main barrier electrical POE protective devices shall be conducted using the pulsedcurrent injection test procedures of Appendix B. All defects found during the acceptancetesting shall be corrected, retested, and shown to provide the required performance.

5.8 Special protective measures. In special cases where HEMP hardness cannot beachieved with the electromagnetic barrier alone (see 4.3.4), special protective measures shallbe implemented. Special protective measures shall not be used as a substitute for an elector-magnetic barrier that satisfies the performance requirements of this standard.

5.8.1 MCS outside the main electromagnetic barrier. Special protective measures shallbe implemented to HEMP harden MCS that are placed outside the electromagnetic barrierIAW provisions of this standard (see 5.1.1). Special protective measures for MCS outside themain barrier may include:

a. Cable, conduit, and local volume shielding.

b. Linear and nonlinear transient suppression/attenuation devices.

c. Equipment-level hardening (reduced coupling cross-section, dielectric means ofsignal and power transport, use of inherently robust components).

d. Remoting sensitive circuits to locations within the protected volume.

e. Automatic recycling features or operator intervention schemes, when the missiontimeline permits.

f. Other hardening measures appropriate for the particular equipment to be protected.

Performance requirements for the special protective measures shall ensure that the upper-bound HEMP-induced peak time-domain current stresses at the equipment level are less thanthe vulnerability thresholds of the equipment.7

5.8.1.1 RF communications antennas outside the main electromagnetic barrier. Mission-critical RF antennas and any associated antenna-mounted electronics, tuning circuits, andantenna cables located outside the main electromagnetic barrier shall be treated as MCS thatare placed outside the electromagnetic barrier. Performance requirements for the HEMPprotection shall ensure that the upper-bound HEMP-induced peak time-domain current stressesat the antenna feed are less than the vulnerability thresholds of the MCS located outside thebarrier.7

MIL-STD-188-125-1

38

5.8.2 MCS inside the main electromagnetic barrier. Special protective measures shall beimplemented to HEMP harden MCS that are within the main electromagnetic barrier, but experience mission-aborting damage or upset during verification testing. Special protectivemeasures for MCS inside the barrier may include cable, conduit, and volume shielding;transient suppression/attenuation devices; equipment-level hardening; remoting sensitivecircuits; automatic recycling; operator intervention features; and other hardening measuresappropriate for the particular equipment to be protected. Performance requirements for thespecial protective measures shall ensure that the upper-bound HEMP-induced peaktime-domain current stresses at the equipment level are less than the vulnerability thresholds ofthe equipment. 7

5.8.3 Special protective volumes.

5.8.3.1 Special protective volumes for piping POEs. When a piping POE waveguidebelow cutoff must be larger than the dimension corresponding to a cutoff frequency of at least1.5 GHz to provide adequate fluid flow and a WBC array insert cannot be used, a specialprotective volume shall be established inside the electromagnetic barrier (figure 6a).

5.8.3.1.1 Special waveguide requirements. A WBC having a cutoff frequency less than 1.5 GHz shall be of the minimum inside diameter consistent with its functional requirements. The length of the waveguide section shall be at least five times the inside diameter. All jointsand couplings in the waveguide section and the penetration through the HEMP shield at thePOE shall be electromagnetically closed. No dielectric lining shall be permitted in thewaveguide section.

5.8.3.1.2 Special protective barriers for piping POEs. A special protective barrier shallcompletely enclose piping which is protected at its POE with a waveguide below cutoff havinga cutoff frequency less than 1.5 GHz. The special protective barrier may be a separate shieldwith protected penetrations, or it may be implemented using the metal walls of the pipingsystem itself (figure 6a). Performance requirements for the special protective barrier shallensure that the total shielding effectiveness, measured through the main electromagneticbarrier and special protective barrier, satisfies at least the minimum requirements shown onfigure 1.

5.8.3.2 Special protective volumes for electrical POEs. When a main barrier protectivedevice cannot be designed to achieve the transient suppression/attenuation performanceprescribed for the class of electrical POE (see 5.7) without interfering with operational signals it is required to pass, a special protective volume shall be established inside the mainelectromagnetic barrier (figure 6b). The special protective volume shall be enclosed by aspecial protective barrier with primary and secondary special electrical POE protective devicesas required to meet the performance requirements prescribed in this standard.

MIL-STD-188-125-1

39

FIGURE 6. Typical special protective volumes.

MIL-STD-188-125-1

40

5.8.3.2.1 Special protective barriers for electrical POEs. A special protective barriershall completely enclose wiring and equipment directly connected to a primary specialelectrical POE protective device. The special protective barrier may be a separate shield, or itmay be implemented using cable and conduit shields and equipment cabinets. Performancerequirements for the special protective barrier shall ensure that the total shieldingeffectiveness, measured through the main electromagnetic barrier and special protectivebarrier, satisfies at least the minimum requirements shown on figure 1.

5.8.3.2.2 Primary special electrical POE protective device requirements. A primaryspecial electrical POE protective device shall be substituted for a main barrier electrical POEprotective device that cannot achieve the prescribed transient suppression/attenuationperformance (see 5.7) without interfering with the operational signals it is required to pass. The primary special protective device shall be designed to provide the maximum transientsuppression/attenuation consistent with its functional requirements. A Norton source withpulse parameters prescribed for the applicable class of electrical POE (see table I), connectedto the penetrating conductor at the primary special POE protective device external terminal,shall produce a residual internal transient stress no greater than its design value and shall notcause device damage or performance degradation.4

5.8.3.2.3 Secondary special electrical POE protective device requirements. When thecombination of the primary special electrical POE protective device and the directly connectedequipment cannot be designed to achieve the transient suppression/attenuation performanceprescribed for the class of electrical POE (see 5.7), a secondary special electrical POEprotective device shall be used (figure 6b). The secondary special electrical POE protectivedevice shall be designed so that the total transient suppression/attenuation, measured throughthe primary special protective device, the connected equipment, and the secondary specialprotective device, satisfies at least the minimum requirements prescribed for the class of POEwithout device damage or performance degradation.4

5.8.3.2.4 MCS in a special protective volume. Special protective measures shall beimplemented as necessary to harden MCS in a special protective volume to the HEMP-inducedstresses that will occur in that volume. Special protective measures for MCS in a specialprotective volume may include cable, conduit, and volume shielding; transient suppression/attenuation devices; equipment-level hardening; remoting sensitive circuits; automaticrecycling; operator intervention features; and other hardening measures appropriate for theparticular equipment to be protected. Performance requirements for the special protectivemeasures shall ensure that the upper-bound HEMP-induced peak time-domain current stressesat the equipment level are less than the vulnerability thresholds for the equipment.7

5.8.4 Acceptance testing for special protective measures.

5.8.4.1 Special protective measures for MCS. Acceptance testing is not required forequipment-level special protective measures installed on MCS IAW with 5.8.1, 5.8.2, and

MIL-STD-188-125-1

41

5.8.3.2.4. HEMP hardness provided by these special protective measures shall bedemonstrated during the verification test program.

5.8.4.2 Special protective barriers. Acceptance testing for all special protective barriersshall be conducted using shielding effectiveness test procedures of Appendix A. Additionally,acceptance testing for all primary and secondary special electrical POE protective devices shallbe conducted using PCI test procedures of Appendix B. All defects found during theacceptance testing shall be corrected, retested, and shown to provide the required performance.

5.9 Reliability and maintainability. The HEMP protection subsystem shall be designedand constructed to be rugged, reliable, and maintainable. Reliability and maintainabilityprogram tasks and requirements shall be included in the facility acquisition specifications toensure that reliability is considered in component selections; to reduce the frequency,complexity, and costs of design-dictated maintenance; and to provide adequate provisioningwith spare HCIs and maintenance tools and supplies.

5.10 Safety and human engineering. Safety and human engineering criteria, principles,and practices shall be applied in the design, selection, and placement of HEMP protectionsubsystem elements. Entryways shall be designed to accommodate expected traffic, andshielded doors shall operate simply with operating forces within human engineering limits. Inspection covers shall be designed for safety and ease of removal and proper reinstallation. Electrical POE protective devices shall provide fail-safe features, such as capacitor dischargeresistors, for protection of personnel during installation, operation, maintenance, and repair.

5.11 Testability. The HEMP protection subsystem shall be designed and constructed toaccommodate quality assurance, acceptance, and verification testing, and HM/HS. The facilityshield shall be accessible for visual inspection at all POEs. Access for periodic shieldingeffectiveness measurements shall be provided, except on the floor shield of a bottom floor andon buried facilities. The built-in shield monitoring capability shall consist of a permanentlyinstalled large loop or a permanently installed shield injection point system, as described inMIL-HDBK-423, or other exciter and sensor elements which will detect significant changes inthe electromagnetic barrier performance. Electrical POE protective devices shall be installedwith accessible PCI drive points and measurement points.

5.12 Corrosion control. Corrosion protection measures shall be implemented in thedesign and construction of the HEMP protection subsystem. The facility shield and POEprotective devices shall be constructed with inherently corrosion-resistant materials or metalsshall be coated or metallurgically processed to resist corrosion. Pockets where water orcondensation can collect shall be avoided, and provision shall be made to inspect above theceiling shield for roof leakage. Buried conduits or cables shall be coated with asphaltcompound, plastic sheaths, or equivalent corrosion protection, and a means for detectingleakage shall be provided. Joints between dissimilar metals shall be avoided and, where

MIL-STD-188-125-1

The determination whether an observed interruption or upset is mission-aborting is the responsibility of the8

operational authority for the facility.

42

required, shall be provided with corrosion preventive measures. Cathodic protection shall beprovided, where required by environmental conditions.

5.13 Configuration management. A hardness configuration management program shallbe implemented during design and construction of the HEMP protection subsystem. Hardnesscritical items and hardness critical processes shall be identified in the facility drawings IAWMIL-STD-100, and installed hardness critical items shall be distinctively marked with DDForms 2639, Hardness Critical Labels, or DD Forms 2640, Hardness Critical Tags, asappropriate. Facility design and installation changes shall be assessed for potential HEMPhardness impacts prior to approval. The affected portions of the HEMP protection subsystemshall be retested when major configuration changes occur after acceptance testing.

5.14 Verification testing. After the HEMP protection system has been accepted andfacility equipment is installed and operational, a verification test program shall be conducted. As a minimum, verification testing shall include CW immersion testing of the electromagneticbarrier, PCI tests at electrical POEs, and additional site-specific tests as needed to demonstrateeffectiveness of special protective measures. All deficiencies identified by the verification testprogram shall be corrected and retested until the required hardness is achieved.

5.14.1 CW immersion testing. CW immersion testing shall be performed IAW procedures of Appendix C. At frequencies where the measurement dynamic range exceeds theattenuation required by figure 1, ratios of illuminating field strength to the internal fieldmeasurements shall be equal to or greater than the minimum shielding effectivenessrequirement. Internal field measurements shall be below the instrumentation noise oroperating signal level in frequency bands where measurement dynamic range is less thanattenuation requirements of figure 1. Internal current measurements, when extrapolated tothreat using equations defined in Appendix C, shall be � 0.1 A, and the peak derivatives of thethreat-extrapolated currents shall be � 1 x 10 A/s. No interference with mission-critical7

communications-electronics or support equipment shall occur.

When approved by the sponsoring agency for the verification test, a thorough program ofshielding effectiveness measurements using procedures of Appendix A and a thorough SELDSsurvey IAW MIL-HDBK-423 guidance may be performed in lieu of the CW immersion test.

5.14.2 PCI verification testing. PCI verification testing shall be performed IAWprocedures of Appendix B. Norms of the measured residual internal transient currents shallnot exceed maximum limits for the applicable classes of electrical POEs. POE protectivedevices shall not be damaged or experience unacceptable performance degradation from thePCI excitations. No time-urgent, mission-aborting damage or upsets of MCS shall occur.8

MIL-STD-188-125-1

43

5.14.3 Verification for special protective measures. Site-specific procedures forverification of special protective measures shall be developed based upon test approaches of 5.14.3.1 and 5.14.3.2. The verification testing shall demonstrate that HEMP-inducedelectromagnetic stresses resulting from facility exposure to the threat environment of MIL-STD-2169 will not cause time-urgent, mission-aborting damage or upsets.8

5.14.3.1 Verification of special protective measures for MCS. Verification testing forMCS hardened with special protective measures shall generally include couplingmeasurements and PCI procedures. The coupling test shall be threat-relatable, such as bypulsed field illumination, PCI, or CW immersion (see Appendix C). MCS cable currents shallbe measured and extrapolated to the upper-bound HEMP-induced response for the MIL-STD-2169 threat environment. The extrapolation shall include a factor of 10 to account foruncontrollable coupling parameters, such as departure from planarity and ground conductivity,and other uncertainties. The upper-bound HEMP-induced currents shall then be used as thedrive levels for the pulsed current injection testing.

Long conductors that connect to the MCS and are directly exposed to the HEMPenvironment shall be PCI tested with injected pulses of the amplitudes and waveformsprescribed in Appendix B.

Cables that connect or are internal to the MCS and are not directly exposed shall also bePCI tested. The injected pulse characteristics shall comply with one of the followingrequirements:

a. Amplitudes equal to the upper-bound, HEMP-induced peak time-domain currentstresses, and waveforms similar to those of the applicable threat-extrapolated currents.

b. Amplitudes and waveforms prescribed in Appendix B for the applicable classes ofelectrical circuits.

These verification test excitations shall not cause time-urgent, mission-aborting damage orupset of MCS.8

5.14.3.2 Verification of special protective barriers. Verification of special protectivebarriers shall include barrier attenuation measurements during CW immersion testing and PCItesting of all primary and secondary special electrical POE protective devices. Amplitudes andwaveforms of the injected pulses shall be as prescribed in Appendix B. In addition tofunctional observations and measurements required by 5.14.3.1, residual internal stresses shallbe measured on conductors that penetrate from the special protective volume into the protectedvolume. Norms of responses measured at test points within the protected volume shall notexceed maximum allowable limits, and the test excitations shall not cause time-urgent,mission-aborting damage or upset of MCS.8

MIL-STD-188-125-1

44

5.15 HM/HS program requirements. Logistics support analysis for the HEMP protectionsubsystem shall be performed during the facility acquisition phase. The logistics supportanalysis shall define the HEMP protection subsystem HM/HS requirements, supply supportrequirements, training requirements, and technical data requirements.

5.15.1 HS/reverification test procedures. Detailed HS/reverification test procedures forthe HEMP protection subsystem shall be developed and used. The HS tasks shall beperformed on a periodic basis as described in the HM/HS program. The reverification testresults shall be correlatable to verification test results and shall have the same pass/fail criteria. The procedures shall identify the tests to be performed, test equipment requirements, safetyprecautions, and other relevant information.

5.15.2 Maintenance and inspection procedures. Detailed procedures for preventivemaintenance and inspection and for repair and replacement of HEMP hardness criticalassemblies or items shall be provided. Preventive maintenance and inspection procedures shallbe designed to be implemented at the organizational maintenance level and shall identify thetasks to be performed, frequency of performance, pass/fail criteria where applicable, safetyprecautions, and other relevant information. Repair and replacement procedures shall identifythe tasks to be performed, hardness requirements including pass/fail criteria, safetyprecautions, and other relevant information.

5.15.3 Supply support requirements. A parts list of the installed HEMP hardness criticalassemblies or items and lists of recommended organizational HEMP protection subsystemspare parts, repair parts, supplies, special tools, and special test equipment shall be provided. The lists shall identify the nomenclature or description of each item, the manufacturer andmanufacturer's part number, the federal stock number when assigned, the required quantity,and other relevant information. All spare hardness critical assemblies, items, and cables shallbe identified using either DD Forms 2639, Hardness Critical Labels, or DD Forms 2640,Hardness Critical Tags, as appropriate.

5.15.4 Training requirements. Training requirements for personnel assigned to a HEMP-hardened facility shall be defined. As a minimum, the training program shall includeorganizational HEMP awareness training for all site personnel and classroom and on-the-jobtraining for HM/HS maintenance personnel. Training materials shall be provided for alltraining to be administered at the organizational level.

5.15.5 Technical data. A HEMP protection subsystem technical manual shall beprovided. As a minimum, the technical manual shall include the following:

a. HEMP protection subsystem description and principles of operation.

b. Maintenance and inspection procedures, repair and replacement procedures, andhardness surveillance test procedures.

MIL-STD-188-125-1

45

c. Supply support requirements.

d. Training requirements.

5.15.6 Delivery. The HEMP protection subsystem technical manual shall be deliveredwith the facility. Recommended organizational HEMP spare parts, repair parts, supplies,special tools, special test equipment, and training materials shall also be delivered with thefacility.

5.15.7 Implementation. HEMP protection subsystem preventive maintenance,inspection, and HS/reverification testing shall be performed IAW the technical manual. Corrective maintenance shall be performed if the HEMP protection subsystem performancedegrades below the minimum requirements of this standard. HS/reverification testing shall beperformed at intervals not exceeding seven years.

MIL-STD-188-125-1

46

6. NOTES

(This section contains information of a general or explanatory nature that may be helpful, butis not mandatory.)

6.1 Intended use. The standard contains minimum requirements and design objectivesfor low-risk HEMP protection of fixed ground-based facilities that perform critical, time-urgent C I missions. The purpose is to standardize design, construction, and test of HEMP4

protection subsystems for these facilities and to thereby ensure the quality and durability of theprotection.

Low-risk HEMP protection is military unique because it is required only for critical C I4

assets that support time-urgent attack warning and retaliatory military missions. While othermilitary and commercial systems may require HEMP protection, there are no commercialrequirements for low-risk hardening.

6.2 Issue of DoDISS. When this standard is used in acquisition, the applicable issue ofthe DoDISS must be cited in the solicitation (see 2.2.1 and 2.3).

6.3 Subject term (key word) listing.

Continuous wave immersionElectromagnetic barrierElectric surge arresterFacility HEMP shieldHardeningHardness verificationHigh-altitude electromagnetic pulseLow-risk HEMP protectionMission-critical systemsNuclear survivabilityPOEPOE protective devicePulsed current injectionShielding effectivenessSpecial protective measuresSurvivability/vulnerabilityTransient suppression/attenuation deviceWaveguide below cutoff

6.4 Changes from previous issue. The margins of this standard are marked with verticallines to indicate where substantive technical changes from the previous issue were made. Thiswas done as a convenience only, and the Government assumes no liability whatsoever for any

MIL-STD-188-125-1

47

inaccuracies in these notations. Bidders and contractors are cautioned to evaluate therequirements of this document based on the entire content, irrespective of the marginalnotations and relationship to the last previous issue.

MIL-STD-188-125-1

APPENDIX A

48

SHIELDING EFFECTIVENESS (SE) TEST PROCEDURES

A.1 GENERAL

A.1.1 Scope. This Appendix is a mandatory part of this standard. The informationcontained herein is intended for compliance. This Appendix establishes procedures formeasuring the shielding effectiveness of the electromagnetic barrier required for low-riskHEMP protection of ground-based facilities with critical, time-urgent missions. Theprocedures are applicable for testing other HEMP-hardened facilities, when specified by theprocurement documentation.

A.1.2 Applications. These procedures shall be used for shielding effectivenessacceptance testing of the facility HEMP shield and aperture POE protective treatments. Theprocedures shall also be performed for acceptance of repairs or installations of new POEprotective devices after construction acceptance, except that only areas affected by the repairor installation are required to be tested. Shielding effectiveness measurements may also beconducted as part of the verification test program.

A.2 REFERENCED DOCUMENTS

A.2.1 Government documents. The following documents form a part of this Appendix tothe extent specified:

DI-NUOR-80928 – Nuclear Survivability Test Plan

DI-NUOR-80929A – Nuclear Survivability Test Report

DNA-EMP-1 – Electromagnetic Pulse (EMP) Security Classification Guide (U)(document is classified S-RD)

(Copies of documents required by contractors in connection with specific acquisition functionsshould be obtained from the contracting activity or as directed by the contracting officer.)

A.2.2 Non-Government publications. The following documents form a part of thisAppendix to the extent specified:

IEEE-Std-299 – Standard for Measuring the Effectiveness of ElectromagneticShielding Enclosures

IEEE-Std-488.1 – Standard Digital Interface for Programmable Instrumentation

MIL-STD-188-125-1

APPENDIX A

49

(Applications for copies should be addressed to the Institute for Electrical and ElectronicsEngineers [IEEE], 445 Hoes Lane, Post Office Box 1331, Piscataway NJ 08855-1331.)

A.3 DEFINITIONS

A.3.1 Test area (or test point) shielding effectiveness. For the purposes of thisprocedure, the frequency-dependent ratio, expressed in decibels (dB), of the received signalwhen the receiving antenna is illuminated by electromagnetic radiation in the test calibrationconfiguration (no shield present) to the received signal through the electromagnetic barrier inthe test measurement configuration. Assuming that antenna voltage proportional to fieldstrength is detected:

where V is the measured signal at the test area (or test point), V is the calibration signal at them c

same frequency and transmitting antenna polarization, and corrections are applied for anydifferences in instrumentation system gain/attenuation between the calibration andmeasurement configurations. Shielding effectiveness values are test method-dependent, anddifferent values may be obtained when time-domain or other frequency-domain measurementtechniques are used.

A.4 GENERAL REQUIREMENTS

A.4.1 General. This HEMP shielding effectiveness test method is similar to IEEE-Std-299, except that the requirements have been modified to evaluate the barrier performance witha stepped-frequency measurement technique using a minimum set of test areas and test points. A transmitting antenna is placed on one side of the electromagnetic barrier on the measurementaxis through the center of each test area (or test point). The receiving antenna is centered onthe test area (or test point) at the opposite side of the barrier. The instrumentation is thenstepped through the measurement frequencies, and the measured data are recorded. Magneticfield shielding effectiveness measurements are made at frequencies from 10 kHz through 20MHz. Resonant range/plane wave shielding effectiveness is measured from 20 MHz through 1 GHz. Selection of test areas and test points, test frequencies, and polarizations of thetransmitting antennas are defined in this Appendix.

A.4.2 Purpose. These procedures define shielding effectiveness, as used in this standard. The purpose of the measurements is to obtain shielding effectiveness data for demonstratingcompliance with facility HEMP shield and aperture POE treatment performance requirements.

MIL-STD-188-125-1

APPENDIX A

50

A.4.3 HEMP protection subsystem test configuration. The shielding effectivenessacceptance test shall be conducted near the conclusion of the construction contract, when thefollowing prerequisite conditions are met. The facility shield assembly shall be completed. All POEs and their POE protective devices, required as part of the construction work, shall beinstalled and in a normal operating condition. Internal and external wiring to conductive POEprotective devices, if provided under the construction contract, shall be in place and connected. Penetrating fiber optic cables, if provided under the construction contract, shall be installed. All interior equipment and finish work under the construction contract shall be completed. Installed equipment may be either operating or nonoperating. A visual shield inspection shallbe performed before starting the measurements to assure that these configuration requirementshave been met.

When these shielding effectiveness measurements are conducted as part of the verificationtest program, the facility shall be in a normal operating configuration and shall be performingactual or simulated mission functions. The HEMP protection subsystem shall be intact.

A.4.4 Analysis requirements. There are no pretest or post-test analyses required for theseprocedures.

A.4.5 Test equipment requirements. Antennas and other test equipment required forshielding effectiveness measurements are identified in table A-I. A typical instrumentationsystem is illustrated in figure A-1.

A.4.6 Operational impact analysis and risk. Since the electromagnetic barrier mustremain intact during conduct of the shielding effectiveness measurement sequence and use ofelectrically noisy equipment must be restricted, construction activity or unusual operations(facility modification, maintenance) may be affected. Radiated signal levels are low andpresent no hazard to equipment, but frequency adjustments may be required to avoid self-interference or interference with nearby facilities. Normal electrical safety precautions apply.

A.4.7 Test plan and procedures. A shielding effectiveness test plan and detailed testprocedures shall be prepared. These may be combined in a single document, or two separatedocuments may be used. As a minimum, the documentation shall contain the followinginformation:

a. A statement of test objectives.

b. Facility identification and description.

MIL-STD-188-125-1

APPENDIX A

51

Equipment Characteristics

Oscillators1 10 kHz – 1 GHz

Power Amplifiers 10 kHz – 1 GHz; power output as required fordynamic range

Preamplifiers 10 kHz – 1 GHz; amplification and noise figureas required for dynamic range

Receivers, Network Analyzers,or Spectrum Analyzers

10 kHz – 1 GHz

Antenna Kit2 10 kHz – 1 GHz

Computer and GPIB Control Interfaces3 As required

Fiber Optic (F/O) Links4 As required

Miscellaneous Cables, Attenuators, and CoaxialSwitches

As required

Oscillators may be integral to the receivers/network or spectrum analyzers, and radio frequency (RF)1

signals may be transmitted through the shield with an appropriate fiber optic link or high-quality, solidmetal-shielded coaxial cable.

Electrostatically shielded loop antennas are required in the low-frequency or magnetic regime2

(10 kHz - 20 MHz). Biconical antennas shall be used in the resonant frequency range (20 MHz toapproximately 100 MHz). Log periodic or equivalent broad band antennas shall be used in the high-frequency or plane wave regime (approximately 100 MHz to 1 GHz). Antennas must radiate andreceive over the prescribed frequency bands and, in conjunction with other test equipment, must satisfythe dynamic range requirement.

Use of a personal computer with an IEEE-488 general purpose interface bus (GPIB), or equivalent, to3

control instrumentation and store test data is strongly recommended.

Use of fiber optic links for transmitting RF or control signals through the shield, as required, is4

strongly recommended.

TABLE A-I. Shielding effectiveness test equipment requirements.

MIL-STD-188-125-1

APPENDIX A

52

FIGURE A-1. Typical shielding effectiveness instrumentation system.

c. Test area identification. The entire surface (including the floor when both sides of|the shield are accessible) of the electromagnetic barrier shall be divided into numbered plane|areas not greater than 3.05 m × 3.05 m (10 ft × 10 ft), as illustrated by the example in figure|A-2. The shielding effectiveness measurement axis (imaginary line between the transmitting|antenna and receiving antenna locations) for each test area shall be normal to the shield surface|and shall pass through the geometric center of the area. A list of POEs, by test area, shall be|included.|

|d. Test point identification. Numbered test points shall be established at all|

architectural, mechanical, and electrical POEs. The measurement axes for test points shall be|normal to the shield surface at the geometric centers of shielded doors, equipment access |

MIL-STD-188-125-1

APPENDIX A

53

FIGURE A-2. Sample test area assignments.

panels, and ventilation waveguide-below-cutoff arrays and at the centerlines of penetrating|pipes or conduits for piping and electrical POEs.|

e. Identification of test frequencies.

f. Test equipment identification by manufacturer, model, and serial number.

g. Detailed measurement procedures.

h. Procedures for marking, repair, and retest of defects.

i. Any deviations from requirements of this Appendix.

j. Data management (including calibration and measurement data quality controlprocedures, data acceptability criteria, preservation of data records, and pass/fail criteria).

k. Safety, including electromagnetic radiation and electrical shock hazards.

MIL-STD-188-125-1

APPENDIX A

54

FIGURE A-3. Typical shielding effectiveness measurement record.

l. Security. (see A.4.9)

m. Test schedule (including priority of measurements).

Data item description DI-NUOR-80928, "Nuclear Survivability Test Plan," shall be used.

A.4.8 Test report requirements. A shielding effectiveness test report shall be prepared. As a minimum, the report shall contain the following information:

a. Facility identification and reference to the applicable test plan.

b. A discussion of any deviations from the test plan and requirements of thisAppendix.

c. Test calibration and measurement data (figure A-3 illustrates a typical data graph).

d. Pass/fail conclusions.

Data item description DI-NUOR-80929A, "Nuclear Survivability Test Report," shall be used.

MIL-STD-188-125-1

APPENDIX A

55

A.4.9 Data classification. Test data may be classified. DNA-EMP-1 and theclassification guide for the specific facility or system should be consulted for guidance.

A.5 DETAILED REQUIREMENTS

A.5.1 Data requirements. For each test area (see A.4.7c) and test point (see A.4.7d),|shielding effectiveness measurements shall be made at test frequencies and for each of two|transmitting and receiving antenna polarizations as follows:|

|a. Test frequencies – Test frequencies shall be spaced approximately logarithmically|

within each decade, with minimum sampling density as follows:||

& 10 kHz – 100 kHz : 20 test frequencies|& 100 kHz – 1 MHz : 20 test frequencies|& 1 MHz – 10 MHz : 40 test frequencies|& 10 MHz – 100 MHz : 150 test frequencies|& 100 MHz – 1 GHz : 150 test frequencies|

|The spacing may be adjusted to avoid discrete system operating frequencies or noise spikes in|the ambient electromagnetic environment.|

|b. Antenna polarizations – Planes of the magnetic loop antennas shall be normal to the|

test area surface in two orientations, at 90 degrees to each other and parallel to the principal|seams in the shield. Dipoles of the biconical and log-periodic antennas shall be parallel to the|test area surface in two orientations, at 90 degrees to each other and parallel to the principal|seams.|

A.5.2 Calibration procedure. Calibrations for all test frequencies and for both|polarizations shall be performed IAW figure A-4. The transmitting and receiving magnetic|antenna loops shall be in the same plane, and the distance between antennas, measured|between the centers of the loops, shall be 3.05 (± 0.05) m (10 ft ± 2 in). Dipoles of the|transmitting and receiving biconical and log-periodic antennas shall be parallel to each other,|and the distance between antennas, measured between the feedpoint connections to the antenna|elements, shall be 3.05 (± 0.05) m.|

|During calibration, no equipment or other electromagnetic reflectors (except ground) shall|

be closer to the antennas than three times the antenna separation. The antennas shall be|1.5–2 m (5–6.6 ft) above ground.|

MIL-STD-188-125-1

APPENDIX A

56

FIGURE A-4. Shielding effectiveness calibration and measurement configurations.

The instrumentation system shall be stepped through the test frequencies, and the received|signal strength for each test frequency and antenna polarization shall be recorded as the|calibration signal (V ) for that configuration. Frequency stepping shall be interrupted asc|necessary to perform antenna and equipment changes.|

|Instrumentation noise data also shall be acquired with the antennas in the calibration|

configurations. The instrumentation system shall be stepped through the test frequencies, with|the power amplifiers deenergized. The received signal strength for each test frequency and|antenna polarization shall be recorded as the instrumentation noise signal (V ) for thatn|configuration. Frequency stepping shall be interrupted as necessary to perform antenna and |

MIL-STD-188-125-1

APPENDIX A

57

equipment changes. The system dynamic range (DR) at each frequency and antenna|polarization is defined as follows:|

|||||

where corrections are applied for any differences in instrumentation system gain/attenuation|between the calibration and instrumentation noise measurement configurations.|

|Test equipment shall be chosen to provide a dynamic range at least 20 dB in excess of the|

shielding effectiveness requirement at each test frequency.|

A.5.3 Measurement procedure. Shielding effectiveness measurements for each test area|and test point and at each test frequency and required antenna polarization shall be performed|as shown in figure A-4. Identical equipment, antennas, cables, and equipment settings (except|attenuator settings) shall be used in the calibration and measurement sequences.|

|The transmitting antenna should normally be placed outside the electromagnetic barrier,|

along the measurement axis centered on the test area (or test point). The receiving antenna|should normally be inside the barrier and shall be centered on the test area (or test point). For|the magnetic field measurements, the loops of the transmitting and receiving antennas shall be|in the same plane. Dipoles of the transmitting and receiving biconical and log-periodic|antennas shall be parallel to each other for the resonant range/plane wave measurements. The|nominal distance from the transmitting antenna reference point (center of a loop antenna or|feedpoint of a biconical or log-periodic antenna) to the test area surface is 2.05 m (6.7 ft), less|the thickness of the shield. The nominal distance from the receiving antenna reference point|to the test area surface is 1 m (3.3 ft), and at least 0.3 m (12.2 in) clearance between the shield|and the closest active point on the antenna shall be maintained. The transmitting and receiving|antenna distances from the shield may be varied by ± 0.5 m (1.6 ft), while maintaining the|total separation of 3.05 m, to eliminate physical interference. The measurement axis may also|be displaced from the center of the test area or test point to eliminate physical interference or|to maintain the receiving antenna clearance from the shield. These variations and|displacements shall be noted in the test report.|

|The instrumentation system shall be stepped through the test frequencies, and the received|

signal strength for each test frequency and antenna polarization shall be recorded as the|measured signal (V ) for that test area (or test point) and configuration. Frequency steppingm|shall be interrupted as necessary to perform antenna and equipment changes. |

MIL-STD-188-125-1

APPENDIX A

When a shielding effectiveness measurement is performed on a test area surface or test point between the barrier9

exterior and a special protective volume, the pass/fail criteria are as specified in the design of that special protectivevolume. A measurement in the adjacent protected volume is also required, to demonstrate that the total attenuationthrough the main barrier and special protective barrier satisfies these pass/fail requirements.

58

A.5.4 Facility ambient noise measurement procedure. Facility ambient noise|measurements are not required, but are recommended at selected measurement locations for|characterizing the operating electromagnetic environment in various parts of the facility and|for investigating below-specification shielding effectiveness readings. Ambient noise|measurements at a test area or test point are made with the receiving antennas in the same|locations and orientations specified for shielding effectiveness measurements (see A.5.3). The|instrumentation system is stepped through the test frequencies, with the power amplifiers|deenergized, and the received signal strength for each frequency and antenna polarization is|recorded as the ambient noise signal (V ) for that test area (or test point) and configuration. a|Frequency stepping is interrupted as necessary to perform antenna and equipment changes.|

|The instrumentation system measurement range (MR) is defined as follows:|

||||||

where corrections are applied for any differences in instrumentation system gain/attenuation|between the calibration and ambient noise measurement configurations.|

|When facility ambient noise limits the measurement range significantly below the|

required dynamic range, the noise source should be eliminated if practical. Interference from|narrow band ambient noise spikes can also be prevented by adjusting the test frequency|selection.|

A.5.5 Pass/fail criteria. The shielding effectiveness pass/fail criteria are shown as a9|function of frequency by figure A-5. The facility HEMP shield and aperture POE protective|treatments shall be considered satisfactory when both of the following criteria are met:|

|a. No sequence of measurements occurs at three consecutive frequencies with the|

measured shielding effectiveness below the minimum requirements curve (figure A-5).||

b. No more than 10 percent of the measurements in any decade (10 kHz – 100 kHz, |100 kHz – 1 MHz, 1 MHz – 10 MHz, 10 MHz – 100 MHz, and 100 MHz – 1 GHz) are below|the minimum requirements.|

MIL-STD-188-125-1

APPENDIX A

59

FIGURE A-5. Minimum HEMP shielding effectiveness requirements.

When making the pass/fail determination, below-specification shielding effectiveness values|can be disregarded if it can be demonstrated that the reading is due to an ambient noise source|that cannot practically be eliminated.|

MIL-STD-188-125-1

APPENDIX B

60

PULSED CURRENT INJECTION (PCI) TEST PROCEDURES

B.1. GENERAL

B.1.1 Scope. This Appendix is a mandatory part of this standard. The informationcontained herein is intended for compliance. This Appendix establishes PCI test proceduresfor electrical point-of-entry (POE) protective devices required for low-risk high-altitudeelectromagnetic pulse (HEMP) protection of ground-based facilities with critical, time-urgentmissions. The procedures are applicable for testing other HEMP-hardened facilities, whenspecified by the procurement documentation.

B.1.2 Applications. These procedures shall be used for acceptance testing afterconstruction of the HEMP protection subsystem and for verification testing of electrical POEprotective treatments after the facility is completed and operational.

B.2. REFERENCED DOCUMENTS

B.2.1 Government documents. The following documents form a part of this Appendix tothe extent specified:

MIL-STD-2169 – High-Altitude Electromagnetic Pulse (HEMP) Environment (U)(document is classified Secret)

MIL-HDBK-423 – High-Altitude Electromagnetic Pulse (HEMP) Protection for Fixed and TransportableGround-Based Facilities, Volume I: Fixed Facilities

DI-NUOR-80928 – Nuclear Survivability Test Plan

DI-NUOR-80929A – Nuclear Survivability Test Report

DNA-EMP-1 – Electromagnetic Pulse (EMP) Security Classification Guide (U)(document is classified S-RD)

(Copies of documents required by contractors in connection with specific acquisition functionsshould be obtained from the contracting activity or as directed by the contracting officer.)

B.2.2 Non-Government publications. The following document forms a part of thisAppendix to the extent specified:

MIL-STD-188-125-1

APPENDIX B

61

IEEE-Std-488.1 – Standard Digital Interface for Programmable Instrumentation

(Applications for copies should be addressed to the Institute for Electrical and ElectronicsEngineers [IEEE], 445 Hoes Lane, Post Office Box 1331, Piscataway NJ 08855-1331.)

B.3 DEFINITIONS

B.3.1 Norms. Scalar quantities that characterize the features of a complicated waveform. Norms used as pass/fail criteria for PCI test residual internal stresses are peak current, peakrate of rise, and root action. These quantities apply to short pulse tests only.

B.3.2 Peak current norm. The maximum absolute value of a current waveform, I(t),expressed in units of amperes, measured from time t = 0 to t = 5 × 10 s.�3

B.3.3 Peak rate of rise norm. The maximum absolute value of the first derivative of acurrent waveform I(t) with respect to time, dI/dt, expressed in units of amperes per second,measured from time t = 0 to t = 5 × 10 s.�3

B.3.4 Root action. The root action norm of a current waveform I(t), in units ofamperes- , is defined by the equation

where t = 0 at the start of the PCI drive pulse.

B.4. GENERAL REQUIREMENTS

B.4.1 General. PCI acceptance testing is used to demonstrate that electrical POEprotective devices, as-installed, perform in accordance with the transient suppression/attenuation requirements of this standard. PCI verification testing confirms the transientsuppression/attenuation performance in operational circuit configurations and demonstratesthat mission-critical systems (MCS) are not damaged or upset by residual internal transientstresses.

The test method couples threat-relatable transients to penetrating conductors at injectionpoints outside the electromagnetic barrier. Injections in both common mode (all penetratingconductors of a cable simultaneously driven with respect to ground) and individual wire-to-ground configurations are required. For purposes of this procedure, ground is a point on thefacility HEMP shield in the vicinity of the POE protective device under test. Residual internal

MIL-STD-188-125-1

APPENDIX B

62

responses are measured, and operation of the MCS is monitored during the verification test todetermine if mission-aborting damage or upsets occur.

The required tests are performed on each penetrating conductor and cable, radiofrequency (RF) antenna shield, and conduit shield. Simultaneous injection of all electricalPOE protective devices, if practicable, is desirable for verification testing.

B.4.2 Purpose.

B.4.2.1 Purposes of PCI acceptance testing. The purposes of PCI testing, as anacceptance test procedure, are as follows:

a. To measure the performance of as-installed conductive POE protective devices.

b. To demonstrate through post-test inspection, performance checks, and response dataanalysis that the protective devices will not be damaged or degraded by threat-relatabletransients.

c. To identify defective devices or faulty installation practices, so that repairs orreplacements can be made.

B.4.2.2 Purposes of PCI verification testing. The purposes of PCI testing, as part of averification test program, are as follows:

a. To measure the performance of conductive POE protective devices in operationalcircuit configurations.

b. To demonstrate through post-test inspection, performance checks, and response dataanalysis that the protective devices will not be damaged or degraded by threat-relatabletransients.

c. To identify defective devices or faulty installation practices, so that repairs orreplacements can be made.

d. To characterize the residual internal transient stresses.

e. To demonstrate that residual internal transient stresses will not cause mission-aborting damage or upsets of the MCS in their various operating states.

f. To provide data for HEMP hardness assessment of the facility and baseline data forthe hardness maintenance/hardness surveillance program.

MIL-STD-188-125-1

APPENDIX B

63

B.4.3 HEMP protection subsystem test configuration.

B.4.3.1 Acceptance test subsystem configuration. PCI testing for acceptance isperformed after the POE protective devices have been installed in the facility. Theelectromagnetic barrier is not required to be complete, but it must be recognized that anincomplete barrier may result in degradations of the POE protective device performance andthe instrumentation signal-to-noise ratio. Equipment which, in the facility operation, willelectrically connect to the POE protective device under test is not required to be powered orinstalled.

B.4.3.2 Verification test facility configuration. When PCI verification testing isconducted, the facility shall be in a normal operating configuration and shall be performingactual or simulated missions. The HEMP protection subsystem shall be intact. Equipmentwhich electrically connects to the POE protective device under test shall be powered andoperating, except as otherwise specified in this procedure.

B.4.4 Pretest analysis requirements. There are no pretest analyses required for PCIacceptance testing. Pretest analysis for PCI verification testing shall be performed todetermine operating states in which the MCS will be tested. An equipment should be tested inmultiple states when the transition produces a significantly different propagation path for theresidual internal transient, significant change in the equipment vulnerability threshold, orsignificant change in the function being performed. A mission-critical transceiver, forexample, should be tested in at least two states—transmitting and receiving—and a digitalinterface should be tested in both the low and high signal states.

B.4.5 Test equipment requirements. Test equipment required for PCI testing is identifiedin table B-I. Current injection pulse generators for all POEs are defined as Norton equivalentgenerators. Therefore, pulse generator requirements are defined in terms of short-circuitcurrent and source impedance. Short-circuit current is defined as current driven through ashort circuit connected to the generator output. Source impedance is defined to be thegenerator peak open-circuit voltage divided by the peak short-circuit current.

B.4.6 Operational impact analysis and risk.

B.4.6.1 Acceptance testing impact. When PCI testing is performed as an acceptance testprocedure, the electromagnetic barrier must remain reasonably intact, such that POE protectivedevice performance and instrumentation signal-to-noise ratio are not excessively degraded. Use of electrically noisy equipment must be restricted in order to achieve the requiredmeasurement sensitivity. Construction activity may, therefore, be affected.

MIL-STD-188-125-1

APPENDIX B

64

Characteristics

Equipment Short Pulse1Intermediate

Pulse 1LongPulse1

Charge Line Pulser (for RFantenna signal conductors)

Pulse Generators2 Up to 5,000-A short-circuitcurrent, source impedance at

least 60 6, and doubleexponential waveform

Up to 250-Ashort-circuit

current, sourceimpedance at least

10 6, doubleexponentialwaveform

Up to 1,000-Ashort-circuit

current, sourceimpedance at least

5 6, doubleexponentialwaveform

Up to 400-A short-circuitcurrent, source impedance at

least 50 6, variable pulse width

Current Sensors(Injected Transient)

10 kHz–750 MHz,0–5,000 A

dc – 10 MHz, 0–250 A

dc – 10 kHz, 0–1,000 A

10 kHz–750 MHz, 0–400 A

Current Sensors(Residual InternalTransient)

100 Hz–750 MHz, 0–100 A,transfer impedance as required

for measurement sensitivity

dc – 10 MHz, 0–250 A

dc – 10 kHz, 0–1,000 A

100 Hz–750 MHz, 0–100 A,transfer impedance as required

for measurement sensitivity

Oscilloscopes orTransientDigitizers3

100 Hz–750 MHz, minimumsensitivity as required formeasurement sensitivity

dc – 10 MHz dc – 10 kHz100 Hz–750 MHz, minimum

sensitivity as required formeasurement sensitivity

Data Recorder3 0–5 ms 0–50 ms 0–100 s 0–5 ms

Preamplifiers 100 Hz–750 MHz, amplificationand noise figure as required for

measurement sensitivity – –

100 Hz–750 MHz,amplification and noise figureas required for measurement

sensitivity

InstrumentationShield and PowerSupplies

As required for isolation frompulse generator

As required forisolation frompulse generator

As required forisolation frompulse generator

As required for isolation frompulse generator

MiscellaneousCables,Attenuators, andDummy LoadResistors

As required As required As required As required

See table B-II for characteristics of the short, intermediate, and long pulses.1

Pulse generator short-circuit current requirements are stated in terms of current delivered through a short circuit at the2

generator output terminals. Source impedance is the ratio of the generator peak open-circuit voltage to the peak short-circuit current. The method of coupling the pulse generator output to the penetrating conductor is not specified. However, connection of the pulse generator into the circuit under test must not interfere with normal circuit operation.

Use of a personal computer with an IEEE-488 general purpose interface bus (GPIB), or equivalent, to control3

instrumentation and store test data on magnetic disk is strongly recommended.

TABLE B-I. PCI test equipment requirements.

MIL-STD-188-125-1

APPENDIX B

65

B.4.6.2 Verification testing impact. During PCI verification testing, the barrier mustremain intact and use of electrically noisy equipment which is not part of the normal siteequipment complement must be restricted; unusual operations (facility modification,maintenance) may be affected. Mission operations can continue normally, except as follows:

a. The circuit and POE protective device under test may be unavailable for normal use;it may be necessary to disconnect unprotected equipment outside the barrier, and the circuitmay be periodically deenergized.

b. A special sequence of activities may be required so that the circuit and facility can betested in their various operating states.

B.4.6.3 Risk. PCI testing requires application of high voltages and large currents. Special high-voltage electrical safety precautions apply. Because of the high injection levels,the risk of POE protective device or equipment damage cannot be completely eliminated. However, the procedures are designed to minimize this risk.

B.4.7 Test plan and procedures.

B.4.7.1 Acceptance test plan. A comprehensive, site-specific test plan and detailed testprocedures for PCI acceptance testing shall be prepared. These may be combined in a singledocument, or two separate documents may be used. As a minimum, the documentation shallcontain the following information:

a. A statement of the test objectives.

b. Facility identification and description (including a site plan, floor plan of theshielded volume, list of shield POEs, and a description of the HEMP protection subsystem).

c. Identification of circuits and POE protective devices to be tested (including circuitfunctions and manufacturers' data sheets and specifications for the protective devices).

d. Identification of test points and injection levels (see table B-II).

e. HEMP simulation and data acquisition equipment description (includingmanufacturer, model and serial numbers, characteristics, and detailed calibration procedures).

f. Detailed test procedures.

MIL-STD-188-125-1

APPENDIX B

66

a.

Ele

ctri

cal P

OE

s, e

xce

pt

RF

an

ten

na

lin

e P

OE

s; d

ou

ble

exp

on

en

tial w

ave

form

s (f

igu

re B

-1).

Cla

ss o

fE

lect

rical

PO

ET

ype

of

Inje

ctio

nP

ea

k S

ho

rt-C

ircu

itC

urr

en

t Î (

A)

So

urc

e I

mp

ed

an

ce1

Z (6

)s

Ris

etim

e-

(s)

R

FW

HM

(s)

Acc

ep

tan

ce T

est

Lo

ad

Imp

ed

an

ce ( 6

)

Co

mm

erc

ial P

ow

er

Lin

es

(In

ters

ite)

Sh

ort

Pu

lse

Sh

ort

Pu

lse

Inte

rme

dia

te P

uls

eIn

term

ed

iate

Pu

lse

Lo

ng

Pu

lse

Lo

ng

Pu

lse

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

5,0

00

2,5

00

25

02

50

1,0

00

5 1,0

00

5

� 6

0

� 6

0

� 1

0

� 1

0

� 5

5

�2

×1

0-8

�2

×1

0-8

�1

.5×

10-6

�1

.5×

10-6

�0

.2�

0.2

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5×

10

-3-3

10

-5×

10

-3-3

20

-25

5 20 -

25

5

No

t a

pp

lica

ble2

2 o

r V

/I4

rate

dra

ted

No

t a

pp

lica

ble2

50

No

t a

pp

lica

ble2

50

Oth

er

Po

we

r L

ine

s (I

ntr

asi

te)

U

nre

stri

cte

d L

ine

sS

ho

rt P

uls

eS

ho

rt P

uls

e

Res

tric

ted

Line

sS

ho

rt P

uls

eS

ho

rt P

uls

e

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

5,0

00

2,5

00

80

0

80

0/

or

50

06

� 6

0

� 6

0

� 6

0

� 6

0

�2

×1

0-8

�2

×1

0-8

�2

×1

0-8

�2

×1

0-8

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

No

t a

pp

lica

ble2

2 o

r V

/I4

rate

dra

ted

No

t a

pp

lica

ble2

2 o

r V

/I4

rate

dra

ted

Au

dio

/Da

ta L

ine

s (I

nte

rsite

)S

ho

rt P

uls

eS

ho

rt P

uls

eIn

term

ed

iate

Pu

lse

Inte

rme

dia

te P

uls

eL

on

g P

uls

eL

on

g P

uls

e

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

,7

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

,7

5,0

00

5,0

00

/ o

r 5

00

6

25

02

50

1,0

00

5 1,0

00

5

� 6

0

� 6

0

� 1

0

� 1

0

� 5

5

�2

×1

0-8

�2

×1

0-8

�1

.5×

10-6

�1

.5×

10-6

�0

.2�

0.2

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5×

10

-3-3

10

-5×

10

-3-3

20 -

25

5 20 –

25

5

No

t a

pp

lica

ble2

50

No

t a

pp

lica

ble2

50

No

t a

pp

lica

ble2

50

Co

ntr

ol/S

ign

al L

ine

s (I

ntr

asi

te)

U

nre

stri

cte

d L

ine

sS

ho

rt P

uls

eS

ho

rt P

uls

e

Res

tric

ted

Line

sS

ho

rt P

uls

eS

ho

rt P

uls

e

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

Co

mm

on

mo

de2

Wir

e-t

o-g

rou

nd3

5,0

00

5,0

00

/ o

r 5

00

6

80

08

00

/ o

r 5

00

6

� 6

0

� 6

0

� 6

0

� 6

0

�2

×1

0-8

�2

×1

0-8

�2

×1

0-8

�2

×1

0-8

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

10

-5.5

×1

0-7

-7

No

t a

pp

lica

ble2

2 o

r V

/I4

rate

dra

ted

No

t a

pp

lica

ble2

2 o

r V

/I4

rate

dra

ted

Co

nd

uit

Sh

ield

sB

uri

ed8

No

nb

uri

ed

Co

nd

uit-

to-g

rou

nd9

Co

nd

uit-

to-g

rou

nd9

80

05

,00

0�

60

60

10-8

�2

×1

0-85

×1

0-5

.5×

10

-7-7

10

-5.5

×1

0-7

-7 2

10 2

10

TA

BLE

B-I

I. P

CI s

ourc

e pa

ram

eter

s, w

avef

orm

s, a

nd a

ccep

tanc

e te

st lo

ads

.

MIL-STD-188-125-1

APPENDIX B

67

TA

BLE

B-I

I. P

CI s

ourc

e pa

ram

eter

s, w

avef

orm

s, a

nd a

ccep

tanc

e te

st lo

ads

- C

on

tinu

ed

.

b.

RF

an

ten

na

lin

e P

OE

s.

Cla

ss o

fE

lect

rica

l PO

ET

ype

of

Inje

ctio

nD

omin

ant R

espo

nse

Fre

quen

cy (

MH

z)11

Pe

ak

Sh

ort

-Cir

cuit

Cur

rent

Î (A

)S

ourc

e Im

peda

nce

1

Z (6

)s

Ris

etim

e -

(s)

R

FW

HM

(s)

Acc

epta

nce

Tes

t Loa

dIm

peda

nce

( 6)

RF

An

ten

na

Lin

eS

hie

ld

Bur

ied8

No

nb

uri

ed

Sh

ield

-to

-gro

un

d12

Sh

ield

-to

-gro

un

d12N

ot

ap

plic

ab

leN

ot

ap

plic

ab

le 8

00

13 5,0

00

13

�6

0�

60

�2

×1

0-8

�2

×1

0-85

×1

0-5

.5×

10

-7-7

10

-5.5

×1

0-7

-7 5

014

50

14

RF

An

ten

na

Lin

eS

ign

al C

on

du

cto

rW

ire

-to

-sh

ield

Wir

e-t

o-s

hie

ld�

30

>3

0T

hre

at-

leve

l11

Th

rea

t-le

vel11

�6

0�

50

�2

×1

0-8

�5

×1

0-95

×1

0-5

.5×

10

-7-7

Va

ria

ble

15 5

014

50

14

Sou

rce

impe

danc

e, Z

, is

defin

ed a

s pu

lser

pea

k tim

e-do

mai

n op

en-c

ircui

t vol

tage

div

ided

by

puls

er p

eak

time-

dom

ain

shor

t-ci

rcui

t cur

rent

.1

s

For

a c

omm

on m

ode

test

, all

pene

trat

ing

cond

ucto

rs in

the

cabl

e ar

e si

mul

tane

ousl

y dr

iven

with

res

pect

to g

roun

d, w

here

gro

und

is a

poi

nt o

n th

e2 fa

cilit

y H

EM

P s

hiel

d in

the

vici

nity

of t

he P

OE

. C

omm

on m

ode

test

s ar

e re

quire

d fo

r ve

rific

atio

n, b

ut th

ey a

re n

ot r

equi

red

for

acce

ptan

ce.

For

a w

ire-t

o-gr

ound

test

, eac

h pe

netr

atin

g co

nduc

tor

in th

e ca

ble

is d

riven

with

res

pect

to g

roun

d, w

here

gro

und

is a

poi

nt o

n th

e fa

cilit

y H

EM

P3 sh

ield

in th

e vi

cini

ty o

f the

PO

E p

rote

ctiv

e de

vice

. W

hich

ever

is s

mal

ler.

V a

nd I

are

the

max

imum

vol

tage

and

cur

rent

rat

ings

of t

he P

OE

pro

tect

ive

devi

ce, r

espe

ctiv

ely.

4ra

ted

rate

d

Th

e lo

ng

pu

lse

pe

ak

sho

rt-c

ircu

it cu

rre

nt

(1,0

00

A)

an

d F

WH

M (

20

-25

s)

are

de

sig

n o

bje

ctiv

es.

A

ny

do

ub

le e

xpo

ne

ntia

l wa

vefo

rm

with

pe

ak

5 shor

t-ci

rcui

t cur

rent

200

A, r

iset

ime �

0.2

s,

an

d p

ea

k cu

rre

nt

x F

WH

M p

rod

uct

2 x

10

A-s

sat

isfie

s th

e m

inim

um r

equi

rem

ent.

4

Whi

chev

er is

larg

er. N

is th

e nu

mbe

r of

pen

etra

ting

cond

ucto

rs in

the

cabl

e.6 In

term

edia

te a

nd lo

ng p

ulse

wire

-to-

grou

nd te

sts

of a

udio

/dat

a lin

es a

re r

equi

red

for

acce

ptan

ce, b

ut th

ey a

re n

ot r

equi

red

for

ver

ifica

tion.

7 An

ante

nna

shie

ld is

con

side

red

burie

d w

hen

it te

rmin

ates

at a

bur

ied

ante

nna

and

less

than

1 m

(3.

3 ft)

of i

ts to

tal l

engt

h is

not

cov

ered

by

eart

h8 or

con

cret

e fil

l. A

con

duit

is c

onsi

dere

d bu

ried

whe

n it

conn

ects

two

prot

ecte

d vo

lum

es a

nd le

ss th

an 1

m (

3.3

ft) o

f its

tota

l len

gth

is n

ot c

over

ed.

For

a c

ondu

it-to

-gro

und

test

, max

imum

feas

ible

leng

th o

f the

con

duit

is d

riven

with

res

pect

to g

roun

d, w

here

gro

und

is a

poi

nt

on th

e fa

cilit

y9 H

EM

P s

hiel

d in

the

vici

nity

of t

he c

ondu

it pe

netr

atio

n. W

iring

inte

rnal

to th

e co

ndui

t is

term

inat

ed a

t the

inst

alle

d eq

uipm

ent,

if pr

esen

t. O

ther

inte

rnal

wiri

ng is

bun

dled

toge

ther

and

term

inat

ed in

10 co

mm

on

2 6

res

isto

rs a

t eac

h en

d. T

he c

ondu

it is

ele

ctro

mag

netic

ally

clo

sed

to th

e fa

cilit

y H

EM

P s

hiel

ds a

t bot

h en

ds.

Th

e d

om

ina

nt

resp

on

se f

req

ue

ncy

(o

r fr

eq

ue

nci

es)

an

d t

hre

at-

leve

l pe

ak

sho

rt-c

ircu

it cu

rre

nt

are

de

term

ine

d f

rom

ext

rap

ola

ted

co

up

ling

11 m

easu

rem

ents

. F

or a

shi

eld-

to-g

roun

d te

st, m

axim

um fe

asib

le le

ngth

of t

he a

nten

na li

ne s

hiel

d is

driv

en w

ith r

espe

ct to

gro

und,

whe

re g

roun

d is

a p

oint

on

the

12 faci

lity

HE

MP

shi

eld

in th

e vi

cini

ty o

f the

PO

E p

rote

ctiv

e de

vice

. D

ou

ble

exp

on

en

tial w

ave

form

(fig

ure

B-1

).13

Sig

nal c

ondu

ctor

term

inat

ed to

the

shie

ld w

ith 5

0 6

. T

he s

hiel

d co

nduc

tor

is e

lect

rical

ly b

onde

d to

the

faci

lity

HE

MP

shi

eld.

14

Out

put w

avef

orm

of t

he c

harg

e lin

e pu

lser

, with

the

leng

th o

f the

cha

rge

line

equa

l to

the

quar

ter-

wav

elen

gth

of th

e do

min

ant r

espo

nse

freq

uenc

y.

15 If th

e P

CI c

urre

nt r

equi

rem

ent e

xcee

ds th

e ca

pabi

lity

of th

e ch

arge

line

pul

ser,

the

shor

t dou

ble-

expo

nent

ial p

ulse

r sh

all b

e u

sed.

MIL-STD-188-125-1

APPENDIX B

68

FIGURE B-1. Double exponential waveform.

g. Any deviations from the requirements of this Appendix.

h. Data management (including data quality control procedures, data acceptabilitycriteria, data processing requirements, annotation and preservation of data records, andpass/fail criteria).

i. Safety, including electromagnetic radiation and electrical shock hazards.

j. Security (see B.4.10).

k. Test schedule (including priority of measurements).

Data item description DI-NUOR-80928, "Nuclear Survivability Tests Plan," shall be used.

B.4.7.2 Verification test plan. A comprehensive, site-specific test plan and detailed testprocedures for PCI verification testing shall be prepared. These may be combined in a singledocument, or two separate documents may be used. As a minimum, the documentation shallcontain the following information:

a. A statement of the test objectives.

MIL-STD-188-125-1

APPENDIX B

69

b. Facility identification and description (including a site plan, floor plan of theshielded volume, list of shield POEs, list of MCS inside and outside the electromagneticbarrier, and a description of the HEMP protective subsystem).

c. Identification of circuits and POE protective devices to be tested (including circuitfunctions and manufacturers' data sheets and specifications for the protective devices).

d. Identification of test points.

e. HEMP simulation and data acquisition equipment description (includingmanufacturer, model and serial numbers, characteristics, and detailed calibration procedures).

f. Detailed test procedures (including system and circuit configuration requirements,equipment operating states, diagrams of the data acquisition system, injection levels [see tableB-II], data requirements, and step-by-step procedures).

g. Any deviations from the requirements of this Appendix.

h. Data management (including data quality control procedures, data acceptabilitycriteria, data processing requirements, annotation and preservation of data records, and pass/fail criteria).

i Safety, including electromagnetic radiation and electrical shock hazards.

j Security (see B.4.10).

k Test schedule (including priority of measurements).

Data item description DI-NUOR-80928, "Nuclear Survivability Tests Plan," shall be used.

B.4.8 Test report requirements.

B.4.8.1 Acceptance test report. A PCI acceptance test report shall be prepared. As aminimum, the test report shall contain the following information:

a. Facility identification and reference to the applicable test plan.

b. A discussion of any deviations from the test plan and requirements of this Appendix.

c. Copies of the measured results, along with sensor calibrations and instrumentationsettings required to convert the data to engineering units.

MIL-STD-188-125-1

APPENDIX B

70

d. A summary table of the norms of the measured internal responses and comparison tothe maximum allowable residual internal response characteristics (see table B-III).

e. Pass/fail conclusions.

Data item description DI-NUOR-80929A, "Nuclear Survivability Test Report," shall be used.

B.4.8.2 Verification test report. A PCI verification test report shall be prepared. As aminimum, the test report shall contain the following information:

a. Facility identification and reference to the applicable test plan.

b. A discussion of any deviations from the test plan and requirements of this Appendix.

c. Copies of the measured results, along with sensor calibrations and instrumentationsettings required to convert the data to engineering units.

d. A summary table of the norms of the measured internal responses and comparison tothe maximum allowable residual internal response characteristics (see table B-III).

e. Test conclusions (including a definitive statement of HEMP hardness of missionfunctions, based on the continuous wave [CW] immersion [see Appendix C] and PCI testresults and supporting analysis).

f. Test chronology (including a sequence of events and identification of failures,upsets, or interference observed and the conditions under which they occurred).

Data item description DI-NUOR-80929, "Nuclear Survivability Test Report," shall be used.

B.4.9 Post-test analysis requirements.

B.4.9.1 Analysis of acceptance test data. Post-test analysis of PCI acceptance measureddata is required for data corrections for probe and instrumentation response characteristics andconversion of results into norms in engineering units.

MIL-STD-188-125-1

APPENDIX B

71

Cla

ss o

f Ele

ctric

al P

OE

sT

ype

of

Inje

ctio

nT

ype

of

Me

asu

rem

en

tP

ea

k C

urr

en

t(A

)P

ea

k R

ate

of

Ris

e(A

/s )

Ro

ot

Act

ion

(A)

Co

mm

erc

ial P

ow

er

Lin

es

(In

ters

ite)

S

hort

Pul

se

Sho

rt P

ulse

Co

mm

on

Mo

de

Wir

e-t

o-g

rou

nd

Bu

lk c

urr

en

tW

ire

cu

rre

nt

�1

0�

10

�1

×1

07

�1

×1

07�

1.6

×1

0-1

�1

.6×

10-1

Inte

rme

dia

te P

uls

e

In

term

ed

iate

Pu

lse

L

ong

Pul

se

Lon

g P

ulse

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Bu

lk c

urr

en

tW

ire

cu

rre

nt

Bu

lk c

urr

en

tW

ire

cu

rre

nt

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

Oth

er

Po

we

r L

ine

s (I

ntr

asi

te)

S

hort

Pul

se

Sho

rt P

ulse

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Bu

lk c

urr

en

tW

ire

cu

rre

nt

�1

0�

10

�1

×1

07

�1

×1

07�

1.6

×1

0-1

�1

.6×

10-1

Au

dio

/Da

ta L

ine

(In

ters

ite)

S

hort

Pul

se

Sho

rt P

ulse

Com

mon

mod

eW

ire

-to

-gro

un

dB

ulk

curr

ent

Wire

cur

rent

�0

.1�

0.1

�1

×1

07

�1

×1

07�

1.6

×1

0-3

�1

.6×

10-3

Inte

rme

dia

te P

uls

e

In

term

ed

iate

Pu

lse

L

ong

Pul

se

Lon

g P

ulse

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Bu

lk c

urr

en

tW

ire

cu

rre

nt

Bu

lk c

urr

en

tW

ire

cu

rre

nt

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

Co

ntr

ol/S

ign

al L

ine

s (I

ntr

asi

te)

Lo

w-V

olta

ge

Lin

es2

Sho

rt P

ulse

Sho

rt P

ulse

Hig

h-V

olta

ge

Lin

es2

Sho

rt P

ulse

Sho

rt P

ulse

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Co

mm

on

mo

de

Wir

e-t

o-g

rou

nd

Bu

lk c

urr

en

tW

ire

cu

rre

nt

Bu

lk c

urr

en

tW

ire

cu

rre

nt

0.1

0.1

1.0

1.0

�1

×1

07

�1

×1

07

�1

×1

07

�1

×1

07

�1

.6×

10-3

�1

.6×

10-3

�1

.6×

10-2

�1

.6×

10-2

TA

BLE

B-I

II.

Max

imum

allo

wab

le r

esid

ual r

espo

nse

char

acte

ristic

s fo

r el

ectr

ical

PO

Es

.

MIL-STD-188-125-1

APPENDIX B

72

TA

BLE

B-I

II.

Max

imum

allo

wab

le r

esid

ual i

nter

nal r

espo

nse

char

acte

ristic

s fo

r el

ectr

ical

PO

Es

- C

on

tinu

ed

.

Cla

ss o

f Ele

ctric

al P

OE

sT

ype

of

Inje

ctio

nT

ype

of

Me

asu

rem

en

tP

ea

k C

urr

en

t(A

)P

ea

k R

ate

of

Ris

e(A

/s)

Ro

ot

Act

ion

(A)

Co

nd

uit

Sh

ield

s

S

ign

al a

nd

Lo

w C

urr

en

t P

ow

er

3

Bu

rie

d o

r N

on

bu

rie

d C

on

du

it

In

term

ed

iate

Cu

rre

nt

Po

we

r3

Bu

rie

d o

r N

on

bu

rie

d C

on

du

it

H

igh

Cu

rre

nt

Po

we

r3

Bu

rie

d o

r N

on

bu

rie

d C

on

du

it

Co

nd

uit-

to-g

rou

nd

Co

nd

uit-

to-g

rou

nd

Co

nd

uit-

to-g

rou

nd

Bu

lk c

urr

en

t

Bu

lk c

urr

en

t

Bu

lk c

urr

en

t

�0

.1

�1

.0

�1

0

�1

×1

07

�1

×1

07

�1

×1

07

�1

.6×

10-3

�1

.6×

10-2

�1

.6×

10-1

RF

An

ten

na

Lin

e S

hie

ld D

rive

C

ore

Con

duct

or (

All

RF

A

nten

na L

ines

)S

hie

ld-t

o-g

rou

nd

Wir

e c

urr

en

t�

0.1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

Sh

ield

Co

nd

uct

or

Sh

ield

-to

-gro

un

dS

hie

ld c

urr

en

t�

0.1

�1

×1

07�

1.6

×1

0-3

RF

An

ten

na

Lin

e C

ore

C

on

du

cto

r D

rive

Co

re C

on

du

cto

r (R

ece

ive

-O

nly

)W

ire

-to

-sh

ield

Wir

e c

urr

en

t�

0.1

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

C

ore

Con

duct

or (

Tra

nsm

it or

T

rans

ceiv

e)W

ire

-to

-sh

ield

Wir

e c

urr

en

t�

1.0

No

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

1

Sh

ield

Co

nd

uct

or

Wir

e-t

o-s

hie

ldS

hie

ld c

urr

en

t�

0.1

�1

×1

07�

1.6

×1

0-3

Pa

ss/f

ail

crite

ria

on

inte

rna

l re

spo

nse

wa

vefo

rm n

orm

s a

re n

ot

spe

cifie

d f

or

inte

rme

dia

te o

r lo

ng

pu

lse

cu

rre

nt

inje

ctio

n t

est

1 seq

ue

nce

s.

Pa

ss/f

ail

crite

ria

on

th

e p

ea

k ra

te o

f ri

se a

nd

ro

ot

act

ion

no

rms

are

no

t sp

eci

fied

fo

r R

F a

nte

nn

a li

ne

sig

na

l co

nd

uct

ors

.

Th

e p

ass

/fa

ilcri

teri

a o

f n

o P

OE

pro

tect

ive

de

vice

da

ma

ge

or

pe

rfo

rma

nce

de

gra

da

tion

als

o a

pp

lies

to P

CI

test

se

qu

en

ces

wh

ere

th

is

no

te d

oe

s n

ot

ap

pe

ar

in t

he

ta

ble

.

Lo

w-v

olta

ge

co

ntr

ol/s

ign

al l

ine

s a

re t

ho

se w

ith a

ma

xim

um

op

era

ting

vo

ltag

e <

90

V.

Hig

h-v

olta

ge

co

ntr

ol/s

ign

al l

ine

s a

re t

ho

se

with

2 ma

xim

um

op

era

ting

vo

ltag

e

� 9

0 V

.

Lo

w c

urr

en

t p

ow

er

line

s a

re t

ho

se w

ith a

ma

xim

um

op

era

ting

cu

rre

nt

< 1

A.

In

term

ed

iate

cu

rre

nt

po

we

r lin

es

are

th

ose

with

ma

xim

um

3 op

era

ting

cu

rre

nt

be

twe

en

1 A

an

d 1

0 A

. H

igh

cu

rre

nt

po

we

r lin

es

are

th

ose

with

ma

xim

um

op

era

ting

cu

rre

nt

> 1

0 A

.

MIL-STD-188-125-1

APPENDIX B

73

Double Exponential Waveform (figure B-1)

Class of Electrical POEPeak Short-Circuit

Current Î (A)Risetime - (s)R

FWHM (s)

Control/Signal Lines(Intrasite)

5,000 � 2×10-8 5×10 –5.5×10-7 -7

TABLE B-IV. Cable shield PCI amplitudes and waveforms.

B.4.9.2 Analysis of verification test data. Post-test analysis of PCI verification measureddata is required for data corrections for probe and instrumentation response characteristics andconversion of results into norms in engineering units. Additional analysis of measured datashall be performed to assist in developing a definitive statement of facility HEMP hardness. Detailed requirements for post-test analysis of PCI verification test results will be establishedby the sponsoring agency for the test. They will generally include calculations of threatresponses from CW immersion and PCI test data, analysis of verification test adequacy,development of hardness conclusions, and recommendations for corrective actions, if required.

B.4.10 Data classification. Test data may be classified. DNA-EMP-1 and theclassification guide for the specific facility or system should be consulted for guidance.

B.4.11 Alternative test methods. When approved by the sponsoring agency, cable shieldinjection may be used for verification testing on shielded intrasite control or signal lines in lieuof the common mode PCI requirement. Maximum required current amplitude and theprescribed waveform for cable shield injection shall be as shown in table B-IV. Intrasite cableshields shall be driven over their entire length by removing or buffering/isolating intermediategrounds and other low-impedance paths to ground along the cable run. Internal responsemeasurements shall be made on the bulk cable. Pass/fail criteria of table B-III apply.

B.5. DETAILED REQUIREMENTS

B.5.1 Test configuration. Typical PCI test configurations are illustrated in figure B-2,and a typical data recording system is illustrated in figure B-3. The pulse generator outputmay be directly coupled to the circuit under test, or it may be capacitively or inductivelycoupled. The external current sensor shall be within 15 cm (6 in) of the external terminal ofthe POE protective device, and there shall be no branches in the wiring between the sensorlocation and the external terminal. The internal current sensor shall be within 15 cm (6 in) ofthe internal terminal of the POE protective device, and there shall be no branches in the wiringbetween the sensor location and the internal terminal.

MIL-STD-188-125-1

APPENDIX B

74

FIGURE B-2. Typical PCI test configurations.

MIL-STD-188-125-1

APPENDIX B

When the external equipment is not designed to withstand the test transients, temporary protection should be10

provided or a dummy load should be used in palce of the external equipment.

75

FIGURE B-3. Typical PCI data recording system.

B.5.1.1 Acceptance test configuration. For PCI performed as acceptance testing, theexternal load shall be an open-circuit termination and the internal load shall be a dummyresistor (see B 5.2.3).

B.5.1.2 Verification test configuration. For PCI verification testing, the external loadshall be the installed site equipment or an equivalent dummy load impedance , which permits10

the circuit under test to be energized and performing actual or simulated functions. Theinternal load for PCI verification testing shall be the installed site equipment, which shall be

MIL-STD-188-125-1

APPENDIX B

When the circuit under test operates at voltages greater than 600 Vac or 600 Vdc and cannot safely be tested11

with power on, PCI verification testing may be performed in a deenergized condition. Switches, relay contacts, and othercircuit interrupters shall be placed in the operating state to simulate the power-on condition.

76

energized and performing actual or simulated functions. Isolators shall be installed on the11

wires under test to direct injected current toward the internal load under test (see figure B-2). The isolators shall be compatible with site equipment in actual or simulated operatingcondition.

B.5.2 Current injection requirements.

B.5.2.1 Electrical POEs, except RF antenna line signal conductors.

B.5.2.1.1 Maximum injection levels. Maximum required short-circuit currentamplitudes, source impedances, and prescribed waveforms for PCI acceptance and verification testing for all classes of electrical POEs, except RF antenna line signal conductors, shall be asshown in table B-II and figure B-1. Common mode PCI injections are required only duringverification testing, and the intermediate and long pulse wire-to-ground tests on intersite audioor data lines are required only for acceptance testing.

B.5.2.1.2 Testing sequence. To minimize the possibility of POE protective device orequipment damage, a series of pulses at increasing amplitudes shall be applied as follows:

a. Pulse at the lowest available current output from the pulse generator. This level shallbe less than 10 percent of the maximum amplitude in table B-II, or less than that amplitudewhich activates any nonlinear components in the POE protective device, whichever is greater.

b. Perform a series of pulses, increasing the amplitude by a factor of approximately twoat each step. When testing several circuits with identical POE protective devices, this series ofintermediate pulses may be abbreviated after the first two samples.

c. Pulse at the maximum required amplitude for the circuit under test. Peak currentshould not exceed 110 percent of the levels listed in table B-II.

This sequence shall be used for both acceptance and verification testing.

CAUTION: Electrical POE protective devices have limited pulse lives. The number oftest pulses delivered to each device, peak currents, and pulse widths should be recorded forinclusion in maintenance records. If the total number of previous pulses on the device exceeds 90 percent of the rated life, devices should be replaced before starting the test.

MIL-STD-188-125-1

APPENDIX B

77

B.5.2.2 RF antenna line signal conductors. The HEMP protection on RF antenna line|signal conductors shall be tested using the general procedure for special protective measures. |The test shall include coupling measurements on the antenna subsystem, PCI testing at the|antenna terminals, and PCI testing of the protected MCS when required by this sequence.|

B.5.2.2.1 Coupling measurements. Coupling measurements shall be made on the antenna|subsystem that includes the antenna, antenna protective device (if provided), associated|electronics and tuning equipment outside the electromagnetic barrier (if provided), the external|RF transmission line, and the main barrier POE protective device (or primary special POE |protective device, if the interior equipment is within a special protective volume) as shown in|figure B-4. The antenna line shall be terminated inside the electromagnetic barrier into a|dummy resistor, having resistance equal to the transmission line characteristic impedance, for|acceptance testing and into the installed site equipment, which shall be energized and|operating, for verification testing. An antenna with tuning circuits outside the electromagnetic|barrier shall be tested at the lowest operating frequency, a midband operating frequency, and|the highest operating frequency. If the antenna subsystem is not available at the time of|facility acceptance from the construction contractor, acceptance testing shall be deferred until|the complete antenna subsystem is installed.|

|Excitation for the coupling measurements shall be supplied by CW immersion (see |

Appendix C) or another threat-relatable method. To the extent practical, the locations and |polarizations of the transmitting antennas shall be chosen to maximize the antenna response. |Measurements of the signal conductor current shall be made at the antenna terminal and on the |protected side of the main barrier (or primary special) POE protective device.|

|Coupling measurements shall be extrapolated to the reasonable-worst-case threat level for|

the MIL-STD-2169 HEMP environment, assuming linear behavior of the antenna subsystem. |The extrapolation shall include a factor of 10 to account for uncontrollable coupling|parameters, such as incident field polarization, and other uncertainties present in the coupling|test (see MIL-HDBK-423), unless a smaller correction can be justified in the extrapolation|analysis. The peak antenna threat-level response current amplitude and dominant response|frequency (or frequencies), indicated by a significant peak in the current response per unit|incident field versus frequency curve, shall be determined. The peak residual internal response|current amplitude shall also be determined.|

|It is not necessary to repeat the coupling measurements during the verification test|

sequence if the configuration of the antenna subsystem and equipment in its vicinity has not |changed between acceptance and verification testing. PCI verification injection levels shall be|determined from the extrapolated acceptance coupling measurements when new coupling|measurements are not required.|

MIL-STD-188-125-1

APPENDIX B

78

FIGURE B-4. Antenna subsystem configuration for coupling measurements and PCI testing.

B.5.2.2.2 Antenna terminal PCI test. PCI testing of an RF antenna line signal conductorPOE shall be performed on the complete antenna subsystem, using injections at the antennaterminals. An antenna with tuning circuits outside the electromagnetic barrier shall be PCItested at the lowest operating frequency, a midband operating frequency, and the highestoperating frequency. An antenna with multiple dominant response frequencies shall be testedat all such frequencies.

The short, double exponential pulse generator shall be used for PCI testing at a dominantresponse frequency � 30 MHz. The charge line pulser, with the charge line length adjusted tothe quarter-wavelength of the dominant response frequency, shall be used for testing atfrequencies greater than 30 MHz. If the required injection level exceeds the charge line pulsercapability, the short double exponential pulse generator shall be employed. The highestrequired injection level shall be that provided at the pulser charge voltage that produces twotimes the extrapolated peak antenna threat-level response current into a short-circuit calibrationload.

MIL-STD-188-125-1

APPENDIX B

When the POE protective device leads into a special protective volume inside the electromagnetic barrier,12

amplitudes and waveforms shall also be recorded on all electrical POEs through the special protective barrier into theprotected volume. The measurements shall be made in the protected volume. Pass/fail criteria for these data are thesame as the pass/fail criteria for other internal response measurements.

79

Injections shall be sequentially performed at approximately 10 percent, 25 percent,|50 percent, and 100 percent of the highest required level. Injected current and residual internal|current waveforms shall be recorded, and peak levels shall be graphed versus pulser charge|voltage. Additional pulses shall then be applied at pulser charge voltages where the responses|are nonlinear functions of the voltage. These additional shots ensure that the largest pulser-|produced peak residual current, which may not occur at the highest injection level, is recorded.|

B.5.2.2.3 Internal equipment PCI test. If the peak residual interior current measured in|the antenna terminal PCI test exceeds the applicable maximum allowable limit (table B-III), a|special protective volume is required to enclose the wiring and equipment directly connected|to the POE protective device. Verification testing of the special protective volume and|enclosed MCS is also required.|

B.5.2.3 Acceptance test load resistance. Ohmic values of the PCI acceptance test internalload resistors for all classes of electrical POEs shall be as listed in table B-II. For wire-to-ground tests, only the penetrating conductor under test requires the specified termination. Forconduit shield tests, internal wiring shall be terminated on normal equipment, if present, andother conductors shall be bundled together and terminated with a common 2-6 resistor at eachend. Wiring which connects the load resistor between the internal terminal of the POEprotective device and its enclosure shall be less than 30 cm (12 in) in length.

B.5.3 Measurements and functional observations.

B.5.3.1 Data requirements. At each step in the testing sequence, for both acceptance andverification testing, the external pulse amplitude and waveform and the internal pulseamplitude and waveform shall be recorded. The internal pulse waveform shall be recorded12

for 5 ms after the start of the PCI short drive pulse, with recording instrument sweep speedsthat allow resolution of the early, intermediate, and late time responses.

B.5.3.2 Verification test functional observations. Operation of facility MCS shall bemonitored during and immediately after the pulse for indications of damage or upset. Adetailed description of any abnormal occurrences shall be prepared for inclusion in the testchronology.

B.5.4 Measurement procedures. PCI test procedures for acceptance and verificationtesting shall be as follows:

MIL-STD-188-125-1

APPENDIX B

80

a. Set up the pulse generator source and data acquisition equipment in the desiredconfiguration and perform calibrations.

b. Deenergize the circuit to be tested for acceptance testing or when required by safetyconsiderations, and install sensors. Reenergize the circuit after sensor installation is complete(verification test only).

c. Perform a noise check of the data recording system to ensure a satisfactory signal-to-noise ratio.

d. Establish the required facility, equipment state, and test configurations.

e. Inject a pulse into the circuit under test (see B.5.2).

f. Record measurement point responses.

g. Record results from the functional monitoring of the MCS (verification test only).

h. Compare measured and observed results to the pass/fail criteria (see B.5.5). If theresults are not satisfactory, halt the test and effect repairs or replacement of the POE protectivedevice. Repeat the PCI test procedure after the corrective action has been completed.

i. Repeat steps e through h at increasing injection levels until the maximum requiredtransient has been injected. (Additional injections may be required for PCI testing of RFantenna line signal conductors at pulser charge voltages where measured responses arenonlinear functions of the voltage [see B.5.2.2].)

j. Continue to the next state to be tested and repeat steps d through i (verification testonly).

k. Deenergize the circuit under test, when required, and remove the sensors and pulsegenerator output connections.

l. Disconnect the electric surge arrester (if installed) from the circuit. Measure thevoltage at 1 mA dc of a metal oxide varistor or the dc breakdown voltage of a spark gap. Compare the measured results to the device specifications. If the results are not satisfactory,effect repairs or replacement of the POE protective device. Repeat the PCI test procedure afterthe corrective action has been completed.

m. Reconnect the electric surge arrester (if installed), and restore the circuit to itsoperational configuration.

MIL-STD-188-125-1

APPENDIX B

When the protected side of the POE protective device is contained within a special protective volume, norms of13

the measured internal responses must not exceed design values for that special protective volume.

The determination of whether an observed interruption or upset impacts the mission is the responsibility of the14

operational authority for the facility.

81

n. Continue to the next circuit to be tested and repeat steps b through m.

B.5.5 Pass/fail criteria.

B.5.5.1 Internal response pass/fail criteria. The POE protective device shall beconsidered satisfactory when both of the following criteria are met:

a. Norms of the measured internal response waveforms, at all short pulse injectionlevels, do not exceed the maximum allowable norm values of table B-III for the applicableclass of electrical POE. If internal responses measured in the PCI verification test cannot be13

discriminated from circuit operating and noise signals, the test shall be repeated in a power-off(acceptance) configuration. The pass/fail determination for internal response norms shall thenbe made using the resulting power-off data.

b. Post-test physical inspection of the POE protective device, measurement of surgearrester (if installed) voltage at 1 mA dc current (for a metal oxide varistor) or dc breakdownvoltage (for a spark gap), and response data analysis indicate that the device has not beendamaged or degraded by the test pulses.

The internal response pass/fail criteria apply for both acceptance and verification testing.

B.5.5.2 Verification test functional pass/fail criteria. Hardening of equipment within theelectromagnetic barrier shall be considered satisfactory when both of the following criteria aremet:

a. No damage to MCS occurred during the PCI verification testing.

b. No mission-aborting interruption of mission-critical functions or upsets of MCSoccurred during the PCI verification testing.14

B.5.5.3 Test failures. Any failure to satisfy the internal response or functional successcriteria shall be considered a HEMP vulnerability. An investigation into the cause of thepossible vulnerability shall be conducted. The condition shall be corrected, if possible, and thePCI verification test sequence shall be repeated.

MIL-STD-188-125-1

APPENDIX C

82

CONTINUOUS WAVE (CW) IMMERSION TEST PROCEDURES

C-1. GENERAL

C.1.1 Scope. This Appendix is a mandatory part of the standard. The informationcontained herein is intended for compliance. This Appendix establishes procedures for CWimmersion testing of the electromagnetic barrier required for low-risk high-altitudeelectromagnetic pulse (HEMP) protection of ground-based facilities with critical, time-urgentmissions. The procedures are applicable for testing other HEMP-hardened facilities, whenspecified by the procurement documentation.

C.1.2 Applications. These procedures shall be used for verification testing of the facilityHEMP shield and aperture point-of-entry (POE) protective treatments.

C.2. REFERENCED DOCUMENTS

C.2.1 Government documents. The following documents form a part of this Appendix tothe extent specified:

MIL-STD-2169 – High-Altitude Electromagnetic Pulse (HEMP) Environment (U)(document is classified Secret)

MIL-HDBK-423 – High-Altitude Electromagnetic Pulse (HEMP)Protection for Fixed and TransportableGround-Based Facilities, Volume I: Fixed Facilities

DI-NUOR-80928 – Nuclear Survivability Test Plan

DI-NUOR-80929A – Nuclear Survivability Test Report

DNA-EMP-1 – Electromagnetic Pulse (EMP) Security Classification Guide (U)(document is classified S-RD)

(Copies of documents required by contractors in connection with specific acquisition functionsshould be obtained from the contracting activity or as directed by the contracting officer.)

C.2.2 Non-Government publications. The following document forms a part of thisAppendix to the extent specified:

IEEE-Std-488.1 – Standard Digital Interface for Programmable Instrumentation

MIL-STD-188-125-1

APPENDIX C

The horizontal component of the electric field or the vertical component of the magnetic field should not be used15

because of the low magnitude of these field components close to a ground. At a height above ground where themagnitude of these components becomes large, this magnitude contains many nulls in the range of 5 MHz to 1 GHz.

83

(Applications for copies should be addressed to the Institute for Electrical and ElectronicsEngineers [IEEE], 445 Hoes Lane, Post Office Box 1331, Piscataway NJ 08855-1331.)

C.3. DEFINITIONS

C.3.1 Illuminating field. The total electromagnetic field, including ground effects, at alocation with respect to the CW transmitting antenna, that would be measured at that point ifthe facility or system under test was not present. Thus, the illuminating field does not includereflections from the facility under test.

C.3.2 Principal component of the illuminating field. A magnetic or electric fieldcomponent that is maximized by the CW transmitting antenna geometry and ground effects. For example, azimuthal magnetic field and vertical electric field are principal components ofthe illuminating field of a vertical monopole antenna over a ground plane.

C.3.3 Reference field. The reference field in a CW immersion test is a measured fieldfor monitoring the output from the transmitting antenna. This field is recorded in the referencechannel of the network analyzer used for data acquisition. The reference sensor must beplaced at a location with respect to the CW transmitting antenna and facility at whichreflections from the test article are negligible at all frequencies of interest, such that thereference measurement has a known relationship to the illuminating field.

To minimize errors in the subsequent data analysis, the reference sensor should measure afield componet that is relatively smooth and flat over the entire frequency range. Examples ofsuch components are the horizontal component of the radial magnetic field parallel to and nearthe ground for a horizontally polarized transmitting antenna and the horizontal component ofthe azimuthal magnetic field or vertical electric field near ground for a vertically polarizedtransmitting antenna.15

The reference field must be recorded for two types of measurements:

a. Field mapping – Measurement of the illuminating field relative to the reference sensorin a field mapping area that is free of electromagnetic reflectors (except ground). The locationof the illuminating field sensor with respect to the transmitting antenna and reference sensormust replicate the facility location (or locations) that will exist during the CW immersion test. This is needed for subsequent data analysis (extrapolation to threat and establishment ofpass/fail conclusions—see C.5.6).

MIL-STD-188-125-1

APPENDIX C

84

b. System response – Measurement of the residual response fields and currents inside thefacility relative to the reference sensor when the facility is illuminated by the CW field.

C.5.6 describes the analysis of the data from the above two measurements to make the pass/fail determination.

C.4. GENERAL REQUIREMENTS

C.4.1 General. The CW immersion test procedure is an element of verification testing,performed as soon as practical after the HEMP-protected facility is completed and operational. The test method illuminates the exterior surface of the electromagnetic barrier with radiatedCW fields and surveys the interior protected volume to identify shield defects and inadequatelyprotected aperture POEs and to provide data for hardness assessment. Both horizontally andvertically polarized transmitting antennas must be used to provide the illuminating fields. Because coupling to exposed external portions of penetrating conductors may not be efficient,CW immersion has limited effectiveness for evaluating conductive POE protection. Therefore,protection provided for penetrating conductors is also evaluated with pulsed current injection(PCI) testing (see Appendix B).

C.4.2 Purpose. The purposes of CW immersion testing are as follows:

a. To measure attenuation of electromagnetic fields in the HEMP portion of thespectrum by linear elements of the as-built electromagnetic barrier.

b. To identify HEMP shield and aperture POE protective device defects, faultyinstallation practices, and inadvertent POEs, so that repairs can be made.

c. To characterize residual internal field and conducted electromagnetic stresses, withinlimitations of the linearity and planarity assumptions, through post-test analysis.

d. To observe operation of the facility for interference or upset (interference whichoccurs as the result of the low-level CW excitation may indicate a circuit which is particularlyvulnerable to HEMP effects).

e. To provide data for HEMP hardness assessment of the facility and baseline data forthe hardness maintenance/hardness surveillance program.

C.4.3 HEMP protection subsystem test configuration. During conduct of the CWimmersion test, the facility shall be in a normal operating configuration and shall beperforming actual or simulated mission functions. The HEMP protection subsystem shall beintact.

MIL-STD-188-125-1

APPENDIX C

85

C.4.4 Pretest analysis requirements. Pretest analysis shall be performed to selecttransmitting antenna locations, reference sensor locations, and measurement points. Transmitting antenna locations shall be chosen to obtain the required illuminating fieldstrength and efficient coupling to all areas on the electromagnetic barrier surface. Referencesensor locations shall be chosen to monitor the transmitting antenna output and determine theilluminating field. Measurement points shall be chosen to provide representative mappings offield responses within the protected volume and special protective volumes and currentresponses within the internal cable plant.

C.4.5 Test equipment requirements. Test equipment required for CW immersion testingis identified in table C-I.

C.4.6 Operational impact analysis and risk. Since the electromagnetic barrier mustremain intact during conduct of the CW immersion test and use of electrically noisy equipmentwhich is not part of the normal site equipment complement must be restricted, unusualoperations (facility modification, maintenance) may be affected. Mission operations cancontinue normally, except that a special sequence of activities may be required so that thefacility can be tested in its various operating states (transmitting, receive-only, etc.). Radiatedsignal levels are low and present no hazard to equipment, but frequency clearance and bands inwhich transmissions must be suppressed may be required to avoid self-interference orinterference with nearby facilities. Normal electrical safety precautions apply.

C.4.7 Test plan and procedures. A comprehensive, site-specific test plan and detailed testprocedures for CW immersion testing shall be prepared. These may be combined into a singledocument, or two separate documents may be used. As a minimum, the test documentationshall contain the following information:

a. A statement of the test objectives.

b. Facility identification and description (including a site plan, floor plan of theprotected volume, list of shield POEs, list of mission-critical equipment inside and outside theelectromagnetic barrier, and a description of the HEMP protection subsystem).

c. Transmitting antenna locations, reference sensor locations, and expectedmeasurement sensitivity of the illumination and instrumentation system.

d. CW illumination and data acquisition equipment identification (includingmanufacturer, model and serial numbers, characteristics, and detailed calibration procedures).

MIL-STD-188-125-1

APPENDIX C

86

Equipment Characteristics

Network Analyzers orEquivalent1

100 kHz–1 GHz, minimum sensitivity as required for measurement sensitivity

Power Amplifiers2 100 kHz–1 GHz, amplification as required for measurement sensitivity

Antennas3 100 kHz–1 GHz

Sensors Free-field, surface current, charge density, and current; 100 kHz–1 GHz

Preamplifiers4 100 kHz–1 GHz, amplification and noise figure as required for measurement sensitivity

Data Recorder1 Multi-channel

Fiber Optic Links5 100 kHz–1 GHz, up to 100 meters in length

Miscellaneous Cablesand Attenuators

As required

Use of a personal computer with an IEEE-488 general purpose interface bus (GPIB), or equivalent, to1

control the network analyzer, the fiber optic (F/O) links, preamplifiers, and data acquisition (includingstorage of test data on magnetic disk or tape) is strongly recommended.

Typically, several linear power amplifiers are required; for example, 150 W (or greater ) for 100 kHz–2

220 MHz, and 10 W for 200 MHz–1 GHz.

In order to cover a broad frequency range, several transmitting antennas may be required. Examples are3

horizontal dipoles and vertical monopoles for frequencies up to 50 MHz and various log-periodic antennasfor both polarizations for frequency ranges such as 30 MHz–100 MHz and 90 MHz to 1 GHz.

TABLE C-I. CW immersion test equipment requirements.

__________________

e. Detailed test procedures (including facility configuration requirements, equipmentoperating states, diagrams of the test configuration, step-by-step procedures, and measurementpoint locations).

f. Any deviations from the requirements of this Appendix.

g. Data management (including data quality control procedures, data acceptabilitycriteria, data processing requirements, annotation and preservation of data records, andpass/fail criteria).

MIL-STD-188-125-1

APPENDIX C

87

h. Safety, including electromagnetic radiation and electrical shock hazards.

i. Security (see C.4.10).

j. Test schedule (including priority of measurements).

Data item description DI-NUOR-80928, "Nuclear Survivability Test Plan", shall be used.

C.4.8 Test report requirements. A CW immersion test report shall be prepared. As aminimum, the test report shall contain the following information:

a. Facility identification and reference to the applicable test plan.

b. A discussion of any deviations from the test plan and requirements of this Appendix.

c. Copies of the measured results, along with sensor calibrations and instrumentationsettings required to convert the data to engineering units. Ideally, the data are acquired with anautomated (and calibrated) data acquisition system which automatically folds in any calibrationfactors, gain, or attenuation settings. In this case, processed data can be provided in place ofthe directly measured results.

d. Test conclusions based on CW immersion and PCI test results and supportinganalysis. A definitive statement of HEMP hardness of mission functions will be made basedon the conclusions of the complete battery of verification tests (including PCI and CW immersion).

e. Test chronology – including a sequence of events and identification of failuresobserved and the conditions under which they occurred.

Data item description DI-NUOR-80929A, "Nuclear Survivability Test Report," shall be used.

C.4.9 Post-test analysis requirements. A post-test analysis of the measured data shall beperformed to assist in developing a definitive statement of facility HEMP hardness. Detailedrequirements for post-test analyses of verification test results will be established by thesponsoring agency for the test. They will generally include calculations of threat responsesfrom CW immersion and PCI test data, analysis of verification test adequacy, development ofhardness conclusions, and recommendations for corrective action, if required.

C.4.10 Data classification. Test data may be classified. DNA-EMP-1 and theclassification guide for the specific facility or system should be consulted for guidance.

MIL-STD-188-125-1

APPENDIX C

88

C.4.11 Alternative test methods. Other types of illumination, such as wide band noise or|repetitive pulsed field radiation, can be substituted for CW illumination if equivalent frequency|coverage and measurement range can be achieved. The test plan and detailed test procedures|shall define the illumination approach, source strength, transmitting antenna positions, and|predicted shield current density distributions. Adequate data acquisition system sensitivity for|verifying the HEMP protection subsystem effectiveness and making pass/fail determinations|shall be demonstrated.|

When CW illumination of a facility is not practical because of physical interference withother facilities in the vicinity, the CW test may be performed using CW current injection onthe outer surface of the electromagnetic barrier. A site-specific CW shield current injectiontest plan and detailed procedures shall define the shield excitation technique, source strength,injection points, and predicted shield current density distributions. Adequate data acquisitionsystem sensitivity for verifying the HEMP protection subsystem effectiveness and makingpass/fail determinations shall be demonstrated.

When approved by the sponsoring agency, a thorough program of shielding effectivenessmeasurements (Appendix A) and a thorough SELDS survey IAW MIL-HDBK-423 guidancemay be used for verification testing in lieu of the CW immersion test.

C.5. DETAILED REQUIREMENTS

C.5.1 Test configuration. A typical CW immersion test configuration is illustrated infigure C-1. Swept or stepped CW excitation, generated by the network analyzer source, ispropagated to the transmitting antenna location via a hardwired or fiber optic link. The signalis amplified and radiated from the antenna (a vertical monopole, horizontal dipole, logperiodic, rhombic or other antenna) to illuminate the facility. The reference sensor, located ina clear area where the measured field has a known relationship to the total field illuminatingthe facility, monitors the source output. Free-field, surface current or charge density, andcurrent sensors monitor the response at measurement points inside (and outside, if desired) theelectromagnetic barrier. Preamplifiers and fiber optic links are used, as required, in themeasurement channels. Reference and measurement point data are monitored on the networkanalyzer and recorded. Figure C-2 illustrates a sample 1 MHz to 100 MHz data record, whereidentical B-dot (time rate of change of the magnetic induction field) sensors are employed inboth channels and the reference channel is a direct measurement of the illuminating field.

C.5.2 Transmitting antenna locations. Transmitting antenna locations shall be chosen toilluminate all areas on the barrier surface with the radiated field excitation. Three or fourlocations around the periphery of the facility will normally be required. The antenna shall be

MIL-STD-188-125-1

APPENDIX C

89

FIGURE C-1. CW immersion testing.

MIL-STD-188-125-1

APPENDIX C

90

FIGURE C-2. CW immersion test record.

MIL-STD-188-125-1

APPENDIX C

Results can be interpreted as plane wave responses when R > � and R > 2D � – where R is the distance16MAX MIN

2

from the antenna to the barrier, � is the wavelength of the lowest radiated frequency, � is the wavelength of theMAX MIN

highest radiated frequency, and D is the antenna characteristic length or largest barrier dimension transverse to thepropagation direction of the illuminating field. For typical CW immersion test geometries, these inequalities aresimultaneously satisfied at frequencies from approximately 5 MHz to approximately 400 MHz. When these inequalitiesare not satisfied, near-field and wave curvature effects may be significant.

91

placed as far from the facility as possible, within physical and measurement sensitivityconstraints.16

C.5.3 Measurement locations. For facilities less than 900 m (10,000 ft ) in shielded2 2

floor area, a minimum of 5 (×3 orthogonal components) electric or magnetic free-fieldmeasurement locations, 3 (×2 orthogonal components) surface current or 3 charge densitymeasurement locations, and 20 current measurement locations throughout the shielded volumeshall be chosen for each transmitting antenna location. For larger facilities, the number ofmeasurement locations shall be increased in proportion to the total shielded floor area.

Measurement points for each transmitting antenna location should be concentrated in the 40 to 50 percent of the protected volume and in special protective volumes physically closestto electromagnetic barrier surfaces that are directly illuminated.

Internal free-field measurement points shall be chosen to provide a representativemapping of field responses within the electromagnetic barrier. The free-field measurementsshall be made in areas that are relatively clear of equipment. The three orthogonal componentsof the field response shall be recorded. Internal magnetic free-field measurements shouldnormally be emphasized.

Internal surface current or charge density measurements shall principally be made atpenetration areas on the electromagnetic barrier. Internal surface current densitymeasurements should normally be emphasized. When measuring surface current density, thetwo orthogonal components of the response shall be recorded.

Internal current measurement points shall be chosen to provide a representative mappingof current responses in the internal cable plant. Current measurements shall be made onselected penetrating cables near their POE protective devices, on selected cables with longinterior runs or layouts producing efficient coupling geometries, and on input cables toselected mission-critical equipment.

An interior electromagnetic survey, with CW excitation applied from each transmittingantenna location, shall be performed to locate areas of maximum response. Particular attentionshould be given to barrier penetration areas. Additional free-field and current measurementpoints shall be chosen where the largest signals are detected during the survey.

MIL-STD-188-125-1

APPENDIX C

The illuminating field is expressed as c × B or E , where c equals the speed of light, B17illuminating illuminating illuminating

equals the magnetic induction field, and E equals the electric field.illuminating

92

C.5.4 Test frequencies. Test data are desired at frequencies from 100 kHz to 1 GHz. Itis usually necessary to divide the frequencies into several bands, selecting different antennas tomaximize the radiation efficiency in the different bands.

C.5.5 Measurement procedures. CW immersion test procedures shall be as follows:

a. Set up the data acquisition equipment in the desired configuration and performcalibrations. Minimum sensitivity of the data acquisition system should be �147 dBm orlower.

b. Set up the transmitting antenna, choose a reference sensor location, and map thefields. The principal component of the illuminating field should be at least 1 V/m from17

1 MHz to 50 MHz and at least 0.1 V/m from 50 MHz to 100 MHz at the point on theelectromagnetic barrier closest to the transmitting antenna. As a design objective, the principalcomponent of the illuminating field should be at least 0.1 V/m from 100 kHz to 1 MHz and0.01 V/m from 100 MHz to 1 GHz.

c. Perform a check of each data acquisition channel to verify link noise immunity. Disconnect the sensor and terminate the sensor cable in its characteristic impedance. Energizethe radiating source, and record the received signal strength as a function of frequency.

d. With the radiating source energized, perform a survey of the area to be monitoredand select the additional measurement locations.

e. Place the sensors and use preamplifiers as required to obtain the desiredmeasurement sensitivity.

f. With the source and data acquisition equipment in a normal configuration, exceptthat the power amplifier is turned off, record the noise and operating signal response at themeasurement point as a function of frequency. Narrow band filter and long sweep timesettings of the network analyzer are necessary.

g. Turn the power amplifier on and record the reference and measurement pointresponses as a function of frequency, using the same filter and sweep time settings employedfor the noise and operating signal measurement.

h. Perform data quality control. Annotate and preserve the data records.

MIL-STD-188-125-1

APPENDIX C

These pass/fail criteria apply to all measurements made in the protected volume. Responses measured in a18

special protective volume must not exceed design values for that special protective volume.

93

i. Record any interference with the operation of facility equipment observed during theCW immersion test. Also record test and operational conditions that existed at the time theinterference was noted.

j. Continue to the next measurement location and repeat steps e through i.

k. When measurements for one transmitting antenna location are completed, continueto the next transmitting antenna location and repeat steps b through j.

C.5.6 Pass/fail criteria.18

C.5.6.1 Internal field measurements. In frequency bands where the measurementdynamic range is less than the required attenuation, internal CW immersion free-field andsurface current or charge density measurements shall be considered satisfactory when there isno observable test point response above the noise and operating signal level.

In the frequency band where the measurement dynamic range is greater than the requiredattenuation (expected to be at least 5 MHz to 1 GHz), internal CW immersion fieldmeasurements shall be considered satisfactory when the test point responses are below theprincipal component of the illuminating field by at least the required attenuation. This successcriterion is expressed by the following equations:

C.5.6.1.1 For internal magnetic induction field measurements.

where

f = frequency (Hz)

7 = angular frequency (s )-1

= 2% f

MIL-STD-188-125-1

APPENDIX C

94

B ( 7 ) = measured component of the magnetic induction field at a test point insideinternal

the electromagnetic barrier (Wb/m /Hz)2

A( 7 ) = minimum attenuation requirement as a function of frequency f

= 10 Hz � f � 10 Hz5 7

= 10 10 Hz < f � 10 Hz�4 7 9

B ( 7 ) = principal component of the illuminating magnetic induction field atilluminating

the point on the electromagnetic barrier closest to the transmittingantenna (Wb/m /Hz)2

C.5.6.1.2 For internal electric field measurements.

where

E (7 ) = measured component of the electric field at a test point inside theinternal

electromagnetic barrier (V/m/Hz)

E (7 ) = principal component of the illuminating electric field at the point illuminating

on the electromagnetic barrier closest to the transmitting antenna (V/m/Hz)

C.5.6.1.3 For internal surface current density measurements.

where

JSinternal(7) = measured surface current density at a test point inside the electromagnetic barrier (A/m/Hz)

MIL-STD-188-125-1

APPENDIX C

95

µ = permeability of free space0

= 4% × 10 H/m�7

C.5.6.1.4 For internal surface charge density measurements.|||||

where||

QSinternal(7) = measured surface charge density at a test point inside the electromagnetic|barrier (C/m /Hz)2|

|� = permittivity of free space0|

= 8.85 × 10 F/m�12|

C.5.6.2 Internal current measurements. Internal CW immersion current measurementsshall be considered satisfactory when the peak value of the threat-extrapolated response,transformed into the time domain, does not exceed 0.1 amperes and the peak derivative doesnot exceed 10 A/s. These success criteria are expressed by the following equations:7

for all time t, where

f = the lowest CW immersion test frequency (Hz)5

f = the highest CW immersion test frequency (Hz)u

I (7) = threat-extrapolated current in the frequency domain (A/Hz)threat

=

MIL-STD-188-125-1

APPENDIX C

96

or

=

I (7) = measured current at a test point inside the electromagnetic barrier (A/Hz)internal

E (7) = early-time HEMP threat electric field in the frequency domain (V/m/Hz)threat

(see MIL-STD-2169)

B (7) = early-time HEMP threat magnetic induction field in the frequency domainthreat

(Wb/m /Hz) (see MIL-STD-2169)2

I (7) = complex conjugate of I (7)*threat threat

C.5.6.3 Interference. Functional monitoring of facility operation shall be consideredsatisfactory when no interference with mission-critical communication-electronics or supportequipment is observed.

C.5.6.4 Test failures. Any failure to satisfy the internal field measurement, internalcurrent measurement, or interference success criteria shall be considered a HEMPvulnerability. An investigation into the cause of the possible vulnerability shall be conducted. The condition shall be corrected, if possible, and the CW immersion test sequence shall berepeated.

97

MIL-STD-188-125-1

Custodians: Preparing activity:Army-CR DSWA - DSNavy-ECAir Force-90DISA - DC1NSA - NS

(Project IXMP-00371)

Review Activities:OASD-IQ,SEArmy-AC,PTNavy-CG,MC,NC,OM,TDAir Force-02,13,17,19,21,29,33,93DIA-DIDISA-DC4DLA-DHDMA-MPJSC-JSUSSPACECOM-US

Civil Agencies Coordinating Activities:TRANSPORTATION-OST